To those who have had bucking....

I have had a "miss" or some bucking problems ever since I changed my plugs & wires. I used Autolite Pro-fit wires & double plat plugs. I have taken the plugs out & re-gapped to no avail. I will be trying again this afternoon, & if it does not work I'll take the wires back for a replacement set.

You sure have got it right, this is a most irritating problem. My symptoms occur with full or low fuel, at any speed just as long as I am under light acceleration. Seems especially bad when the engine has warmed up. Have you noticed something similar? My next step will be to replace fuel filter & O2 sensors.

I'll keep you posted.

Mark, I had a similar problem a few years back. I would be driving on the highway at speed and all of a sudden my car would just jerk maybe once or twice. It was strong enough that I could spill my coffee if I wasn't careful. Dealership never could find any kind of problem later that year I did change my fuel filter and did some other stuff and, "touch wood" that problem has never come back since. I have no idea if those things helped.

noticed a substantial reduction in bucking after I replaced the DPFE.

What's that?

Based on your suggestion I too replaced my plugs with Autolite double plat plugs. But my problem went away for days, only to return. And it always starts the same way, first while the a/c is on and gradually gets worse and worse until it's doing the same thing almost all the time now. It's never at WOT, it's always just under medium load before the ATX will kick down. And sometimes while sitting at idle. I ran that car HARD to Seattle from Portland without one single stutter. I drove it 50 miles to work and back the next day. Then yesterday it was 80 degrees and I drove it home with the a/c on and it started missing/bucking/stuttering. My car has 85K and no belt change yet. And we have the CVT (sp?) Zetec engine with the ATX. It's getting more than a little frustrating. I'm thinking about changing the plug wires since maybe when the plugs are brand new and they have almost zero resistance the plug wires are sending enough voltage to fire them. And maybe after a little time the plugs get just enough carbon on them to force the plug wires to short out somewhere. I don't know but if anyone has a suggestion please say so, thanks again, Ken

I have exactly the same car and exactly the same problem. See my post towards the end of this thread and PLEASE let me know if you trace the problem back to something. I don't want to put in a new set of plugs and trade it in, but I'm close to that solution, Ken 99 Silver Frost SE Zetec ATX.

Here's a great link to Ford's DPFE and all it's problems. It looks like this may be it. I'll let you know, Kennard 99 Silverfrost SE Zetec ATX, wheels, Sumho's, sound system, high output blue headlight bulbs, Audi side marker lights where the SE badges were (an easy, easy mod BTW) and more to come (IF I get this stutter problem figured out) Here's the link; http://www.cnnw.net/~fourty/dpfe.htm

Almost the same car. Mine is a V-6. Heading off to park under a tree & play mechanic now ... BRB.

Differential Pressure Feedback Exhaust sensor. Interesting.
How exactly could that cause bucking?

BTW Kennard, you can set up signatures under "my home" after you have logged in. No need to type all that stuff up every time you post!

My issues seem more prominent toward the end of the tank and when the vehicle is first started for the day. Once I break 3000rpm it seems to disapear/get covered up. I'm still waiting to hear from someone though that can answer the first question I posted regarding if the bucking is there through the whole tank and just not as noticeable in the top portion. Anyone?

Originally posted by lauraq:
"touch wood"

LMAO.I think u mean "knock on wood". We don't need you touching your wood in front of us.

-Tavis

From my post above:

"My symptoms occur with full or low fuel, at any speed just as long as I am under light acceleration. Seems especially bad when the engine has warmed up. Have you noticed something similar?"

Awwww, man! I haven't had lunch yet. Please stop that.

I had a similar problem once before. It turned out to be the throtle position sensor. I replaced it and the problem stopped instantly.

Ray

Originally posted by akrump47:
I still have bucking. Cleaned the TB and put new Motorcraft plugs in. Dealer replaced the clutch and slave cylinder too, it still wont go away. It happens when lifting foot on or off the throttle. I wish I could figure out what is causing it ...

I have the same. Cleaning the MAF and resetting PCM
solves it for about 1-2 weeks, then it comes back.

Can it be the IACV ?

T.

Mine is full tank or empty, worse when warmed up, and never at WOT, only under medium to light throttle load. Never had problem til I changed plugs, so I R&R'd them with new dub plat Autolites (again) and it went away for a couple days. Just returned yesterday driving home. It seems to start when the a/c is on, then gets progreesively worse. But never had a CEL. Ken

Originally posted by Kennard:
Mine is full tank or empty, worse when warmed up, and never at WOT, only under medium to light throttle load.

Describes mine perfectly. Dealer already replaced the IAC and there was no change. Someone suggested the TPS, that seems reasonable. I'll do some more research on this DPFE sensor too . . . the only other cause would be if the dealer either didnt install or bleed the clutch correctly . . .

ummmm...hate to be the "bearer of bad tidings" but I had the same problems that everyone here is discussing.....then the car literally died on the highway!! It started with the small bucking, then it became more and more frequent until the car began bucking and stalling getting onto the highway monday morning. After 5 days (and countless calls) I was told that the fuel pump was shot. One of the techs at the dealership was curious....did I always try to coax "extra mileage" out of the car when the low fuel light came on? I said I did, and on a regular basis, as everyone knows how pessimistic our fuel guages are. He said he wasn't positive, but that it could have been a contributing factor in my fuel pumps demise(with the fuel sloshing around a nearly empty tank, it does make some sense;a dry fuel pump pick-up is not a good thing). He also mentioned something about the pick-up screen that is on the pump itself(which I don't think I could get to with my "returnless" 2000)And believe me, i tried EVERYTHING you guys had done, short of ripping the engine apart, to address the problem.

Well I was mistaken on the amount in the tank thing. It is evident at all times but more so when the car is still cold. As it warms up it seems to get better but doesn't all together go away. I'm wondering about O2 sensors but that would throw a cel right? Even with headers on a 95 correct?

To further my atemps to diagnos this issue. I pulled the pcm fuse. the car still is not cured and the problem was there imediately. So that tells me it is mechanical and not "learned" When I try to rev the engine in neutral it stumbles till about 3000rpm then goes about its business as per usual. You can really hear it through the intake when it is stumbleing. Gonna clean the maf this weekend and the UIM but I'd be surprised if that cleared this up. Anymore sugestions?

I had similar bucking problems on a previous car. Any time I lighltly tipped into the throttle with a gear engaged, the car would buck and lurch forward. Not nice unless you want coffee stains on your shirt.

The problem was a crack in an intake hose between the MAF and the throttle body. This crack let in enough unmetered air to throw off the fuel:air mixture significantly at part throttle. WOT was never a problem because the amount of unmetered air relative to metered air was very small.

Anyway, a little duct tape on the intake pipe eliminated the bucking, and verified that that was the problem.

So, for all you with bucking problems, I would look for a source of unmetered air.

Originally posted by Munson:
I had similar bucking problems on a previous car. Any time I lighltly tipped into the throttle with a gear engaged, the car would buck and lurch forward. Not nice unless you want coffee stains on your shirt.

The problem was a crack in an intake hose between the MAF and the throttle body. This crack let in enough unmetered air to throw off the fuel:air mixture significantly at part throttle. WOT was never a problem because the amount of unmetered air relative to metered air was very small.

Anyway, a little duct tape on the intake pipe eliminated the bucking, and verified that that was the problem.

So, for all you with bucking problems, I would look for a source of unmetered air.

i'll check that out, i have a similar problem with the hesitation or bucking but i also have my engine light on also. i posted in the trouble shooting section, please check and give some 2 cents.

Originally posted by Munson:
I had similar bucking problems on a previous car. Any time I lighltly tipped into the throttle with a gear engaged, the car would buck and lurch forward. Not nice unless you want coffee stains on your shirt.

The problem was a crack in an intake hose between the MAF and the throttle body. This crack let in enough unmetered air to throw off the fuel:air mixture significantly at part throttle. WOT was never a problem because the amount of unmetered air relative to metered air was very small.

Anyway, a little duct tape on the intake pipe eliminated the bucking, and verified that that was the problem.

So, for all you with bucking problems, I would look for a source of unmetered air.

i'll check that out, i have a similar problem with the hesitation or bucking but i also have my engine light on also. i posted in the trouble shooting section, please check and give some 2 cents.

sorry for the double post, the computer is being dumb

I won't be using duct tape, but I will look for leaks - thanks.

I tried re-gapping the plugs last night. Problem got worse when I opened them up to .056. Problem was less severe if I pushed the gap down to .050, but still present.

During this process I noticed that the forward bank of plugs seemed a bit fouled compared to the plugs by the fire wall. I'm gonna try an O2 sensor change - they're due anyway.

In the weeks leading up to this problem, I also noticed a little "dead zone" in the throttle. A spot that I hold the throttle at cruise. When I push the throttle through this little area, I would get just a bit of hesitation. If the O2 sensors don't work, I'll get it hooked up at the $tealer next Friday & see what they come up with.

Originally posted by Munson:
I had similar bucking problems on a previous car. Any time I lighltly tipped into the throttle with a gear engaged, the car would buck and lurch forward. Not nice unless you want coffee stains on your shirt.

The problem was a crack in an intake hose between the MAF and the throttle body. This crack let in enough unmetered air to throw off the fuel:air mixture significantly at part throttle. WOT was never a problem because the amount of unmetered air relative to metered air was very small.

Anyway, a little duct tape on the intake pipe eliminated the bucking, and verified that that was the problem.

So, for all you with bucking problems, I would look for a source of unmetered air.

I will definitely check this out ... thx

Originally posted by wontgrowup:
ummmm...hate to be the "bearer of bad tidings" but I had the same problems that everyone here is discussing.....then the car literally died on the highway!! It started with the small bucking, then it became more and more frequent until the car began bucking and stalling getting onto the highway monday morning. After 5 days (and countless calls) I was told that the fuel pump was shot. One of the techs at the dealership was curious....did I always try to coax "extra mileage" out of the car when the low fuel light came on? I said I did, and on a regular basis, as everyone knows how pessimistic our fuel guages are. He said he wasn't positive, but that it could have been a contributing factor in my fuel pumps demise(with the fuel sloshing around a nearly empty tank, it does make some sense;a dry fuel pump pick-up is not a good thing). He also mentioned something about the pick-up screen that is on the pump itself(which I don't think I could get to with my "returnless" 2000)And believe me, i tried EVERYTHING you guys had done, short of ripping the engine apart, to address the problem.

Hmmm, this doesn't sound all that positive but to my knowledge our 'low fuel light' has been on 2 or 3 times. My wife drives the Tour 99% of the time. I have the E-350, 15 pass, V-10 Club Wagon Econoline, and I don't need no stinking bucking, hahaha. But seriously you know how women are, the tank never gets below 1/4 full, ever. So it's doubtful that this is my problem, but possible. So let's see; it could be the throttle position sensor, the DPFE, a leak in the air inlet, the MAF, the O2 sensor, what else ? Yowzers, it's never easy is it ? This problem seems to be prevalent in all small Ford engines. I-4's, V-6's of various sizes and others according to the DPFE site I visited. So it seems if we find a common part in all these engines we should be able to trace it down a little more. But hey I do appreciate all y'alls input. It's definitely helped cause I know alot more now than I did a few days ago, Ken

This is what worked for me. I did two things then took the car for a drive. I dis-connected the plug for the Throttle Position Sensor & re-connected it several times just in case there was a poor connection there

. My second effort was to remove & clean the MAF. Very tricky. I used an alcohol based spay cleaner that would leave no residue. Sprayed the MAF wires liberally a couple of times, let air dry, re-installed & it drove like a champ.

Now I'm gonna re-gap my plugs to spec & head to the races!!

I hope you guys have similar luck. Those leak suggestions sounded on target too, so don't give up too quickly.

JimR

Originally posted by Kennard:

Originally posted by wontgrowup:
ummmm...hate to be the "bearer of bad tidings" but I had the same problems that everyone here is discussing.....then the car literally died on the highway!! It started with the small bucking, then it became more and more frequent until the car began bucking and stalling getting onto the highway monday morning. After 5 days (and countless calls) I was told that the fuel pump was shot. One of the techs at the dealership was curious....did I always try to coax "extra mileage" out of the car when the low fuel light came on? I said I did, and on a regular basis, as everyone knows how pessimistic our fuel guages are. He said he wasn't positive, but that it could have been a contributing factor in my fuel pumps demise(with the fuel sloshing around a nearly empty tank, it does make some sense;a dry fuel pump pick-up is not a good thing). He also mentioned something about the pick-up screen that is on the pump itself(which I don't think I could get to with my "returnless" 2000)And believe me, i tried EVERYTHING you guys had done, short of ripping the engine apart, to address the problem.

Hmmm, this doesn't sound all that positive but to my knowledge our 'low fuel light' has been on 2 or 3 times. My wife drives the Tour 99% of the time. I have the E-350, 15 pass, V-10 Club Wagon Econoline, and I don't need no stinking bucking, hahaha. But seriously you know how women are, the tank never gets below 1/4 full, ever. So it's doubtful that this is my problem, but possible. So let's see; it could be the throttle position sensor, the DPFE, a leak in the air inlet, the MAF, the O2 sensor, what else ? Yowzers, it's never easy is it ? This problem seems to be prevalent in all small Ford engines. I-4's, V-6's of various sizes and others according to the DPFE site I visited. So it seems if we find a common part in all these engines we should be able to trace it down a little more. But hey I do appreciate all y'alls input. It's definitely helped cause I know alot more now than I did a few days ago, Ken

Maybe someone should check and see how prevalent this problem is. I believe I have a similar problem with my Contour (98 Sport-SE, 6cyl. 5speed) It "jerks" when i lightly step on the gas or let off the gas with a gear engaged. It is more noticeable with the a/c on and also seems more noticeable in 1st-3rd gear, although that may just be me. I didn't think of it as a major problem, but an annoyance. Perhaps I should rethink the situation. I'm not a big poster here and don't know anyone at the board, but some of you that do might want to ask around and see if anyone else has had this "minor" annoyance. My car is the first and only standard I have driven thus far and I attributed the jerking to something that I was doing wrong (I am also the only person that has actually gotten to drive my car any reasonable distance since I bought it.)

I have really bad bucking when my car gets below half a tank. Orginally two months ago the car wouldn't start, replaced the fuel filter and it worked again. But since then i have had this problem with bucking. I am positive it has something to do with the fuel pump. Now that I know my car has been running on low voltage, and the a/c running all the time finally did it in, I am wondering if I had low volatage the fuel pump. No way to tell until i find out about my volatage problem.
-Greg

It turns out it is my secondaries. They are stuck open. Will make another post for this. Glad I know the problem and managed to clean the UIM/LIM in the process.

Okay, I'm a girl that doesn't know much about cars, and I really don't want to take my car back to the dealership, but I'm having the same problem and I need help!! 2000 Contour--V6--owned since 2001, never had a tune-up. I have called it "chugging", but bucking is a much more accurate description for what's happening! When my car has less than 1/4 tank of gas, it bucks during the acceleration in 2nd and 3rd gear. If I continue to accelerate through the bucking, I can almost feel it correct itself. Almost like there was something in the way of the gas flow, and all of the sudden it gets spit out of the way! You like my technical vocabulary? Anyway, how can I try and fix this without doing major diagnostic work on it? Is it possible? My dad just changed the fuel filter two days ago, and it's still happening! It gets MUCH worse once past 1/8 tank. A month or so ago, I tried Dry Gas treatment, and that helped only because I filled the tank up at the same time!

Help!

It sounds like you have the classic fuel pump issues descibed in this and other bucking threads. Do you have a warranty still? If so I'd be inclined to go into the dealership and encourage them to by pass all the testing they will want to do and find a way to charge you for and set them straight off to the fuel pump. If not and you or your dad or someone else are so mechanically inclined there is a write up on here how to fix the problem yourself. Hope that helps.

Originally posted by mbb41:
It sounds like you have the classic fuel pump issues descibed in this and other bucking threads. Do you have a warranty still? If so I'd be inclined to go into the dealership and encourage them to by pass all the testing they will want to do and find a way to charge you for and set them straight off to the fuel pump. If not and you or your dad or someone else are so mechanically inclined there is a write up on here how to fix the problem yourself. Hope that helps.

Are you of the opinion that this is a problem in all Contours ? Is this something I also should be looking into ? Why does the problem go away with fresh plugs ? Why do you think the problem started within a couple weeks of swapping out the original plugs ? May it have been conicidence in my case ? BTW I do not expect a miracle, but you seem pretty knowledgeable so I'm asking your opinion only, thanks, Ken, 99 SE Zetec Atx.

Originally posted by Kennard:

Originally posted by mbb41:
It sounds like you have the classic fuel pump issues descibed in this and other bucking threads. Do you have a warranty still? If so I'd be inclined to go into the dealership and encourage them to by pass all the testing they will want to do and find a way to charge you for and set them straight off to the fuel pump. If not and you or your dad or someone else are so mechanically inclined there is a write up on here how to fix the problem yourself. Hope that helps.

Are you of the opinion that this is a problem in all Contours ? Is this something I also should be looking into ? Why does the problem go away with fresh plugs ? Why do you think the problem started within a couple weeks of swapping out the original plugs ? May it have been conicidence in my case ? BTW I do not expect a miracle, but you seem pretty knowledgeable so I'm asking your opinion only, thanks, Ken, 99 SE Zetec Atx.

Well given my response was to the post above me and not yours. Might that clear it up better for you. For the record I'm not of the opinion that this happens to all Tours. However again the post I was responding to has classic symtoms. If you read through the whole post you probably noticed my problem has turned out to be the secondaries being pinned open. To think some people do it on purpose.

In your case I don't recall did you say you did your fuel filter yet? Or your plugs? Failing those 2 items I would move to the ignition coil (less probable but could make sense) or the MAF. By replacing your plugs you get some great spark from the new ones that may mask your symptons temporaily leading me to guess that your problem never has gone away yet.

No I have not looked into the fuel filter issue yet. But yes, with new fresh plugs the problem alleviates for a couple days. With premium fuel it bucks less than with reg. When the engine is cold she bucks not. Until I changed out the original plugs at 85K it never, ever missed a beat in it's life. It bucks more with the a/c on. It never misses at any throttle position other than 10-35%-ish. Once the Atx kicks down on the freeway it's smooth as ever. The dealer said; "uh, duh, I put it on the diagnostic machine, but it says everything is OK. And you didn't have a Cel did you" ? (it's a scary to see where mechanics are heading these days. I doubt one of them could do a standard tune-up on a non-compter car anymore) I had our Ranger pick-up in the shop 5 different times to 3 different Ford dealers because it pinged ALL the time. Do you think those idiots could figure it out ? HA !!! Finally the service manager pulls me aside like he's going to give me some giant revelation or tell me a state secret and says "uh, look, my 95 1/2 ton pick-up does exactly the same thing. And I've never been able to figure it out either, I just turn the radio up". After I got over my disbelief I couldn't do anything but hang my head and walk away. So this forum seems to be the only chance to remedy this problem. But I believe you are correct, the new plugs only masks the problem, not cures it. So I need to make the next logical step down the path to repair. I will look at the MAF and then try the coil. I also read of the DPFE going bad in lots and lots of Fords. I have also read of the O2 sensor needing replacement. So I will go after some of those first as I have no idea where the DPFE is or what it looks like. But thanks for your help even if it wasn't directly to my post, I have never been shy about chiming in. Whether to ask for help or to offer it, Ken

No problem. With my last bout of bucking. Before last winter. I turned out to be a bad O2 sensor. If there is no code then I'd still be inclinded to look at the maf first.

Originally posted by mbb41:
No problem. With my last bout of bucking. Before last winter. I turned out to be a bad O2 sensor. If there is no code then I'd still be inclinded to look at the maf first.

Yes thank you, I will. I think I will try the MAF, the O2, check for an air leak in the intake and pull the screen out of the fuel filter. Those all seem to be the simplest and most likely. And contrary to most males natures, instead of rebuilding the engine first, I will start with the simplest items, then move forward, Hee Hee, Ken.

Let us know if the MAF helps.

My problem has returned, so it was not the TPS (I unplugged it), IAC (I isolated it by plugging the air hose), or a leak in the intake gasket. I also replace the IAC & EGR valve gaskets, the plugs & wires again. I also replaced the coil pack, now I have a spare.

I wanted to change the fuel filter & install a fuel pressure gauge next. I will also try to find a way to bypass the MAF or get a substitute from somewhere to see if that makes a difference.

(sigh) This is driving me NUTZ!!!

Originally posted by TourDeForce:
Let us know if the MAF helps.

My problem has returned, so it was not the TPS (I unplugged it), IAC (I isolated it by plugging the air hose), or a leak in the intake gasket. I also replace the IAC & EGR valve gaskets, the plugs & wires again. I also replaced the coil pack, now I have a spare.

I wanted to change the fuel filter & install a fuel pressure gauge next. I will also try to find a way to bypass the MAF or get a substitute from somewhere to see if that makes a difference.

(sigh) This is driving me NUTZ!!!

Does your problem go away temporarily when you swap out the plugs for new Autolites (or whatever) ? Mine will, in fact mine never started until I changed the plugs. Anyone have this problem ? Ken 99 SE Zetec Atx.

Mine started after I changed the plugs too. But I did not go away with the second set. I do sometimes manage to get it to go away if I reset the PCM, but it is back the next time I start up.

Because of the plug coincidence, I am beginning to suspect the IMRC because that is the only other thing I touched really. I moved it aside & turned it upside-down while I did the change.

I've had a bucking problem for a few months now, but it's ONLY when I let off the gas, mainly between 2-3K rpms. Could that still be the fuel pump? I have new plugs and wires. New fuel filter. The bucking gets REALLY bad when I take the O/D off. Makes a rumbling/burbling almost muted V8 w/ headers sound, but not quite, obviously (especially when going down a hill). Could this be the transmission? The fluid is a bit overdue to be changed. I had to wait for my tranny cooler and shift kit to get here. I can't figure it out. It did stall on me once when it was cold and I pulled out going uphill. Anyone else experience this?

I've never seen it, but you may have a moose problem. Have you done the "Throttle Hang" fix? Check the "How To" section & the "Common Problems" area to check this out. It may give you some ideas about what problem you may have.

Have you checked to see if your KKM imploded? Just a guess on my part, but they have been known to do that.

No, it's not the old moose. It did it even when I had the CTA intake pipe installed. I thought too that it might have been the KKM because my last one had a small tear in it, so I got a used one in good condition. It SEEMED to go away for about a day and then it came back. I noticed earlier today that when I'm just cruising along at around 2-3K, if I hit the pedal real quick it kicks down pretty rough. I guess that could be a sign of the tranny fluid in need of a good changing. Could also be my Superchip. Just got it reprogrammed last year. This seemed to happen not too long after I reinstalled it. It's clean and in there as good as it gets, so maybe someone at Superchips messed up my shift points somehow. I guess tomorrow I'm finally going to try and remove it, reset the computer and see what happens w/o it installed.

Originally posted by TourDeForce:
Mine started after I changed the plugs too. But I did not go away with the second set. I do sometimes manage to get it to go away if I reset the PCM, but it is back the next time I start up.

Because of the plug coincidence, I am beginning to suspect the IMRC because that is the only other thing I touched really. I moved it aside & turned it upside-down while I did the change.

I did the same, swapped out plugs again, the problem went away for 3 days, then returned. IMRC ? Please elaborate, I was thinking maybe bad plug wires. Have you made that change ? I just gotta think it's something in the ignition system. I had no stuttering, I changed plugs, had stuttering, changed plugs had no stuttering for a couple days, then it returned. But maybe as somehere who seems to be quite a bit more knowledgeable than I said, the new plugs just mask the problem. And I believe he's correct. But I have stock airbox, stock exhaust, the only mod I have engine wise is a Borla style, stainless steel muffler. So, yes, I am frustrated, if only our local Ford dealers cared about us (I mean other than when a sleazebag salesguy walks through the service area and says "my that's a pretty Tour, I have a list of people wanting to buy our good, used Tour trades. You probably are wanting to trade that old, used up Contour on a new Taurus wagon aren't ya" ?) Ken 99 SE

Sigh, $tealerships...

I did get a second set of plugs & plug wires from a different parts store & the symptom is identical.

I opened up my IMRC (might have been a mistake since the thing was VERY well weather sealed). There appears to be nothing in there that could get messed up by moving it around - An electric motor, some gears, a circuit board & the cable coming in. I thought the IMRC might be cracking the secondaries open a bit when I started the car, I'll need to get my frau to help with this test so I can check/feel for any movement of the linkage. Kinda makes sense since the symptom is most noticeable when the engine is warmed up.

I moved the cable a bit to get it over the engine lift loop instead of under the notch, but I don't think that will help. A while back I did a TB clean & didn't replace my TB gasket with the new one. I'll try sticking the TB gasket on & re-checking the EGR valve to make sure its not ruptured. I'm also going to check the DPFE vacuum hoses to be sure those are snug. This is really making me crazy.

I'm trying like hell to islolate items before I start replacing parts. Sometimes I just feel like bringing it to the dealer & have them plug it into their computer so I can see what is going on with all the various parts. Maybe I can invest in one of those diagnostic programs for my PC.

Originally posted by TourDeForce:
Sigh, $tealerships...

I did get a second set of plugs & plug wires from a different parts store & the symptom is identical.

I opened up my IMRC (might have been a mistake since the thing was VERY well weather sealed). There appears to be nothing in there that could get messed up by moving it around - An electric motor, some gears, a circuit board & the cable coming in. I thought the IMRC might be cracking the secondaries open a bit when I started the car, I'll need to get my frau to help with this test so I can check/feel for any movement of the linkage. Kinda makes sense since the symptom is most noticeable when the engine is warmed up.

I moved the cable a bit to get it over the engine lift loop instead of under the notch, but I don't think that will help. A while back I did a TB clean & didn't replace my TB gasket with the new one. I'll try sticking the TB gasket on & re-checking the EGR valve to make sure its not ruptured. I'm also going to check the DPFE vacuum hoses to be sure those are snug. This is really making me crazy.

I'm trying like hell to islolate items before I start replacing parts. Sometimes I just feel like bringing it to the dealer & have them plug it into their computer so I can see what is going on with all the various parts. Maybe I can invest in one of those diagnostic programs for my PC.

Well I have my fingers crossed that you'll find the problem, and believe me, I will do the same for you. Thanks for your input, I'm sorry but I have no idea what IMRC means. But it sounds like you do and it sounds like something I won't mess with. But I've tried the Ford dealer, they couldn't find anything after hooking it up on their diagnostic machine, Ken 99 SE hot rod.

No luck yet.

Fuel filter & a replacement MAF are in my sights. (sigh) This is such a nice car when running well.

Originally posted by TourDeForce:
No luck yet.

Fuel filter & a replacement MAF are in my sights. (sigh) This is such a nice car when running well.

Yes it's pretty easy to see why this car in it's Mondeo form is so popular in Europe. Why will americans flock to european cars like crazy, but then turn their nose up at a european car that says Contour on it ? Our car has been a blast to have, it's quick enough to make you grin, it'll go around corners fast enough to scare you, is a very attractive package and gets 30 mpg. But if I can't get a handle on this bucking I'll drop a set of plugs in her and trade it for a Benz, you can buy a 5 year old, $90,000 car for less than $20,000 nowadays. Low miles, immaculate condition, the whole nine yards. But I'd prefer to keep the little Tour, it has been dead reliable and like I said, it's fun to drive and just different enough so you don't look like every other friggin Civic with a fart pipe and wheels on it driving on every street in america. "Oh gosh how original, I see you have a Honda, wow, you don't see those evryday now do you ?" HAHAHAHA, Ken

You might want to re-consider the Benz idea. I've seen data on their lack of reliability that is kinda scary.

I personally like Jags - especially now that the retro styling makes them look so sweet. I have not done much reliability research on them, but I can get hold of '99 XJ8s for under $25,000. I'll put up with some gremlins to drive one of those.

Originally posted by TourDeForce:
You might want to re-consider the Benz idea. I've seen data on their lack of reliability that is kinda scary.

I personally like Jags - especially now that the retro styling makes them look so sweet. I have not done much reliability research on them, but I can get hold of '99 XJ8s for under $25,000. I'll put up with some gremlins to drive one of those.

My wife likes the Jag too, and it is her car. But I have had great luck with my previous MB's. And one time I was stopped dead on the freeway in my 420 SEL in the snow because there was a wreck in front of me. And a full sized Ford pick-up hit me over at 60 miles per hour. It cost $13,000 to fix the car but I walked away unscathed, and it didn't even bend the frame. Those cars are engineered like no other car on earth. And believe it or not, for under $20K you can buy a mid-to late 90's car with factory warranty left on them. I'm looking at a 95 S-500 with 66K miles. The dealer is asking only $23K and I offered him $15K. But we'll meet somewhere in the middle. But everytime a mechanic lifts the hood of a Benz, you can count on a thousand dollar bill. But they don't lift the hood very often, they are remarkably well built. Personal preference I guess, I just like the way the Benz looks. Don't get me wrong, the Jags are gorgeous, they're just smaller and I'm 6' 5" and 230 pounds, so I like big cars. No, don't ask how I drive the Tour, cause I don't very often, my wife is 5' 1" and 110.

well, i have the same problem. and here is the list of what i replaced.

first get a obdII test done. i bet u will get a misfire in one of your cylinders.

ive replaced the plugs 4 times, 2 sets of wires.
plugs fixed problem for couple of days so maybe i thought i was over tighting the plugs. got a torque wrech and made sure i didnt. and the problem was immediate on the last plug change.

changed ignition coil.
changed injectors.
gutted precats thought i had a pluged precats.

changed main cat.

spent a total of over 800 dollars tryting to fix this stupid ass problem. with still no luck. im about to clean the maf right now. wish me luck. hey if u wanna talk some more about his problem contact me with a pm or my aim name is ws3912

Of all the MBs you could have chosen, the 420 SEL is one of my favorites although I've never owned a Mercedes. I like big cars too, & the styling of that one, in particular, appeals to me. I've owned an 81 and 88 Grand Marquis - I really loved those V-8s. I put nearly 200,000 on each before I let them go. It is interesting to note that the V-8 cars got better fuel economy than my 2.7 BMW or my 1.3 RX-7, the RX-7 being the worst.

On to the Tour. I changed the MAF - no improvement. I am going to change the plugs yet again & put in a new fuel filter, tonight.

Originally posted by NITROS:
well, i have the same problem. and here is the list of what i replaced.

first get a obdII test done. i bet u will get a misfire in one of your cylinders.

ive replaced the plugs 4 times, 2 sets of wires.
plugs fixed problem for couple of days so maybe i thought i was over tighting the plugs. got a torque wrech and made sure i didnt. and the problem was immediate on the last plug change.

changed ignition coil.
changed injectors.
gutted precats thought i had a pluged precats.

changed main cat.

spent a total of over 800 dollars tryting to fix this stupid ass problem. with still no luck. im about to clean the maf right now. wish me luck. hey if u wanna talk some more about his problem contact me with a pm or my aim name is ws3912

Well if it's any consolation, I feel for ya. Your problem sure sounds exactly like mine. When I use premium gas it bucks less. Sometimes it's bad, sometimes it's not. Warmer weather seems to make it worse, but not always. Sometimes it will 'miss' at idle, but never, ever at wide open throttle. It's worse with the a/c on. I put in new plugs, and it goes away for a couple days. I would put in the old plugs that I first removed but I threw them away, they were in bad shape, but it didn't buck. And of course, no CEL ever. And it wouldn't buck for the service guy at the local Ford dealership. But it bucked on the way home from there. I've called and talked the the service mgr several times. He has never heard of anyone having this problem. On the Ford truck board there is a whole group of people with this problem, and they say it's the DPFE. I'm lost,,,,,,

Originally posted by TourDeForce:
I am going to change the plugs yet again & put in a new fuel filter, tonight.

Where is it ? How is it changed ? I want to try this too.

As far as the Benz goes, you really ought to just shop around a little and see what they go for, you'd be surprised how cheap they are. I had 560 SEL badges on my 420, I put 560 SEC badges on my 380 SEC. I'm going to put S-600 badges on the S-320. They're fun cars because a 10 year old one that you spent $15K for looks like a new, $100K car.

HAHA!!! Fake badges! How repulsively ricey!

I think I'll put twin-turbo, V-12, & AWD badges on my 'Tour, that'll add about 1200 HP to it & an 8 second quarter mile will be easy - even with ATX!

funny!

At any rate (poor english), I haven't looked for the fuel filter, but I saw a post that said it's under the car near the right rear wheel. I picked up a fuel filter last night, & just got back from another AP store with fresh plugs. I'll grab a TB gasket at the dealer in the morning, since I'll be there to pick up some parts for my mothers car.

Originally posted by TourDeForce:
HAHA!!! Fake badges! How repulsively ricey!

I think I'll put twin-turbo, V-12, & AWD badges on my 'Tour, that'll add about 1200 HP to it & an 8 second quarter mile will be easy - even with ATX!

funny!

But see, that's the GREAT part about it ? Most MB owners are so snooty, they have their noses 10 feet in the air. So here's a guy who spends 1/10th of what they did, who drinks beer out of the bottle driving the same car,(almost) but with the $130K cars badges ! It's awesome ! All of a sudden you're 'one of them' and making fun of them and they don't even know it. If they knew I was a hot rodder, car racer, beer drinker, champagne hater with a re-badged Benz they'd go fruit. And it also pokes fun at the ricers with all their doo-dads on the 90 hp Civics with their 3 foot wings and ground scraping front air dams. Life is good, now if I could only get my 4 cyl Ford to quit bucking, life would be perfect.

Originally posted by TourDeForce:

At any rate (poor english), I haven't looked for the fuel filter, but I saw a post that said it's under the car near the right rear wheel. I picked up a fuel filter last night, & just got back from another AP store with fresh plugs. I'll grab a TB gasket at the dealer in the morning, since I'll be there to pick up some parts for my mothers car.

Here's something interesting I came across on the MSN "find out how reliable your car is" site. The 99 Ford Contour w/the 2.0 liter Zetec was rated 2nd highest for problems, with this addendum;

An occasional problem on this vehicle is the failure of the variable camshaft timing solenoid and/or sprocket.(2.0l Zetec Only)The cost to repair the variable camshaft timing solenoid and/or sprocket is estimated to range from approximately $244.00 to $636.00 for the parts and $175.00 labor.All prices are estimates based on $65 per flat rate hour and do not include diagnostic time or any applicable sales tax.

I wonder if this could be our problem ???

we have been having the bucking problem for a while now, changed numerous items including fuel filter, battery, egr valve, ect... goes away and comes back. uaually goes away after adding a fuel injection cleaner and it is only noticeable when the tank is low on fuel...my question is this: I see that a few people have suggested changing the fuel pump or cleaning the screen. Has anyone done this? Did it fix the problem. From reading I don't see that anyone has tried the fuel pump.

(%

Originally posted by Mr. Ed:
we have been having the bucking problem for a while now, ... only noticeable when the tank is low on fuel ...my question is this: I see that a few people have suggested changing the fuel pump or cleaning the screen. Has anyone done this? Did it fix the problem. From reading I don't see that anyone has tried the fuel pump. %

Thanks for the suggestion, but the item above in bold is the difference. My problem is all the time, full tank or empty, & it nearly disappears at WOT. A bad/clogged fuel pump would likely not do that. Additionally, I like to try the less expensive & easy stuff before I dawn my mechanics fatigues.

My problem turned out to be the double platinum plugs. I either got two bad sets in a row, or my car just does not like them. I installed a set of OE single platinum plugs & it has been flawless since.

I must confess that I may have toasted the first set of double plats by having my plug wires hooked up wrong. My second set, however, came with a new set of plug wires & I was VERY meticulous about how everthing went together, so no excuses there.

To the rest of you, check your plug wires:

fire wall
-------------
coil pack:
465 <-------- ** pay particular attention here - I got dyslexic **
321

Engine cylinders:
123
456

Good luck everybody! Be sure to post when you all solve your bucking/hesitation problems.

By the way, when I got this figured out, I had not yet installed a new fuel filter, so it wasn't that. I'll be installing the filter later this weekend.

I remember reading that review before I bought my V-6. I don't think the Duratecs have that variable timing thingy - do they guys?

Been two days now. Still running sweet!

Originally posted by TourDeForce:

Thanks for the suggestion, but the item above in bold is the difference. My problem is all the time, full tank or empty, & it nearly disappears at WOT. A bad/clogged fuel pump would likely not do that. Additionally, I like to try the less expensive & easy stuff before I dawn my mechanics fatigues.

My problem turned out to be the double platinum plugs. I either got two bad sets in a row, or my car just does not like them. I installed a set of OE single platinum plugs & it has been flawless since.

I must confess that I may have toasted the first set of double plats by having my plug wires hooked up wrong. My second set, however, came with a new set of plug wires & I was VERY meticulous about how everthing went together, so no excuses there.

To the rest of you, check your plug wires:

fire wall
-------------
coil pack:
465 <-------- ** pay particular attention here - I got dyslexic **
321

Engine cylinders:
123
456

Good luck everybody! Be sure to post when you all solve your bucking/hesitation problems.

By the way, when I got this figured out, I had not yet installed a new fuel filter, so it wasn't that. I'll be installing the filter later this weekend.

I was thinking this morning the very same thing. I almost brought it this AM and dropped it off at the Ford dealer with instructions to "Fix it no matter WHAT". But I thought I would first ask what plugs are in it from the factory ? I NEVER had these problems prior to switching out the plugs. I put Autolite dbl plts in and a couple weeks later she started missing. On someone's suggestion here I replaced the plugs with another set of Autolite dbl plats and the problem went away for 3 days, but then returned with a vengeance. So on the way home I'll get what you got and R+R my set. I just have to believe that it's plugs, not the fuel filter, not the MAF, not the DPFE, nothing but the plugs. And maybe the plugs themselves aren't bad until they go into a Zetec motor ? I dunno, but I do know that I will not use them again. Thanks for all your input, I'll keep my fingers crossed that your problem stays away for good, adios.

Originally posted by TourDeForce:
Been two days now. Still running sweet!

FYI; !!!! The Ford dealer said "with the style of ignition system in the Zetec, the plugs can CERTAINLY cause 'bucking or misfiring'. So if any of you are having this problem, and have anything other than the factory style plugs, IE; Autolite double platinums, CHANGE THEM OUT. I went to Schucks to buy my plugs and they pushed the Autolite dbl plt on me because they're $4 each. Fortunately I saved my receipt and I'll go get my money back, for one set at least. But even if I couldn't, if this fixes the problem and I almost guarantee it will, I would have spent thousands elsewhere. Ken

Originally posted by TourDeForce:

My problem turned out to be the double platinum plugs. I either got two bad sets in a row, or my car just does not like them. I installed a set of OE single platinum plugs & it has been flawless since.

AHA ! According to the Ford parts guy (NOT the service guy, he's a SpEd) "the Zetec (and possibly the Duratec too?) takes a special fine wire plug. It will fire under low voltage whereas the non OE plugs won't", which is why at WOT my car ran fine, and at part throttle and at idle it would miss. Un-FREEKIN-believable !!! All this stress and work and talking and asking, and it's nothing but the plugs. So to any of you experiencing bucking who have just changed their plugs, go IMMEDIATELY to your local Ford dealer and get the specific plug for your application. The parts guy said "you'll see the catalog number is extremely long because there are many specific plugs for some of these Ford engines". It may not help you all, but I'm betting it will help alot of you. Good luck, Ken 99 SE Zetec

Originally posted by Kennard:

Originally posted by TourDeForce:

My problem turned out to be the double platinum plugs. I either got two bad sets in a row, or my car just does not like them. I installed a set of OE single platinum plugs & it has been flawless since.

AHA ! According to the Ford parts guy (NOT the service guy, he's a SpEd) "the Zetec (and possibly the Duratec too?) takes a special fine wire plug. It will fire under low voltage whereas the non OE plugs won't", which is why at WOT my car ran fine, and at part throttle and at idle it would miss. Un-FREEKIN-believable !!! All this stress and work and talking and asking, and it's nothing but the plugs. So to any of you experiencing bucking who have just changed their plugs, go IMMEDIATELY to your local Ford dealer and get the specific plug for your application. The parts guy said "you'll see the catalog number is extremely long because there are many specific plugs for some of these Ford engines". It may not help you all, but I'm betting it will help alot of you. Good luck, Ken 99 SE Zetec

KUDOS to you Ken for going the extra mile & doing some technical research for us!! Thanks man!

Originally posted by TourDeForce:

Originally posted by Kennard:

Originally posted by TourDeForce:

My problem turned out to be the double platinum plugs. I either got two bad sets in a row, or my car just does not like them. I installed a set of OE single platinum plugs & it has been flawless since.

KUDOS to you Ken for going the extra mile & doing some technical research for us!! Thanks man!

You did it, I read your post and asked myself "why does it matter with the make of plug ?" And did what came naturally. Anyway, it's just so bitchin having my little hot rod back. It was not happy with the bucking, and now she's got a smile on her face. Ken 99 SE Tour Zetec, ATX

"It will fire under low voltage whereas the non OE plugs won't"

Does the ignition system raise the spark voltage in open loop?

Originally posted by LI-SVT:
"It will fire under low voltage whereas the non OE plugs won't"

Does the ignition system raise the spark voltage in open loop?

I do not know that, sorry. I just know, through the process of elimination, that at low rpm's, or low rpm's with any electrical accessories on, including a/c, that my car would miss, which then caused it to buck. The Ford parts guy told me that non-OE plugs, although the non-Ford parts houses will tell you that the Autolites and other accessory plugs are interchangeable, will not work properly. Because you have to have the fine wire, low resistance plugs. When my car is at idle and the headlights and especially with the a/c also on, it dims the lights when the a/c cycles. So I know the elec system is not outting out beau coup power to the ignition system either. And my car only missed at idle, and at low rpm while driving. Once I tipped into the throttle and built some revs it would run fine. And once I had brand new plugs in it, with low resistance (because they were new and perfect and non carboned) the car would run good. But the slightest amount of resistance in the Autolites and the car would start to miss, and buck. The Motorcraft plugs are duh bomb. I have no missing, no bucking, nothing but pure, sweet, Ford horsepower, yahoo !!! Ken 99 Silver Frost SE Zetec ATX

Thanks, for the I have your problem exactly except I have the Duratec engine. I will replace with Motorcraft at first opportunity. I don't have much faith in the dealership would anybody know the part number for the OE plugs for a 99 SE 2.5 Duratec. I am so looking forwad to getting my car back to pre plug change condition. Thanks

I had a similar problem after the 100K mile plug change. After numerous code readings, dead ends, and about $1400, it was cured by two things: (a) autolite double-platinum plugs (took care of part of the problem) and (b) 9mm plug wires (I had previously replaced the wires with dealer-supplied new wires, which did zip).

The forum did supply the info about the plugs. Plus, you get your choice of colors!

Originally posted by pctour:
Thanks, for the I have your problem exactly except I have the Duratec engine. I will replace with Motorcraft at first opportunity. I don't have much faith in the dealership would anybody know the part number for the OE plugs for a 99 SE 2.5 Duratec. I am so looking forwad to getting my car back to pre plug change condition. Thanks

Here's a cut-and-paste of a reply I made this evening to another post ...

Here's what happened to my '98 CSVT ... and how it was fixed.

I had the engine "bucking" problem at low/no throttle described in previous posts. It began with uneven accel and a change in the exhaust note, gradually worsened into a severe and re-creatable misfire-like condition (that did cause it to throw codes -- ultimately irrelevant -- and light up the CEL three times), then got to the point where the engine began to flat-out quit under load.

Because the car was at 54.8k, the basics were covered first: replaced fuel filter (Purolator), plugs and wires (Motorcraft). No money wasted -- but no fix, either.

Long story made short: the conscientious guys at the independent repair shop I've been using since my relo to Pittsburgh (Vince's Automotive on Rte 19 in Perrysville, for CEGer's in Pittsburgh) first rescanned the codes, then found a TSB that looked like a possible match with my problem: erratic engine performance triggering multiple codes. It was a match -- A 7-volt wire at the right-rear of the engine compartment, feeding power to 4 sensors, was being chafed at the right-rear engine lift mount; its sheathing had been worn through. Every time engine movement (or Dave, the tech at Vince's) brought it into contact with metal, the four sensors would freak, causing a misfire and/or kill the engine.

Sheathing was repaired; the chafing point of contact was covered with a short section of (I think) neoprene tubing; and the problem is gone.

Do you have a picture of this wire?? I am having bucking problems with my csvt too!!

Originally posted by David2k3:

Do you have a picture of this wire?? I am having bucking problems with my csvt too!!

Sorry, I don't. I wasn't working on the car at that point.

I'll get the details from the tech who diagnosed and fixed the problem, and post it.

Originally posted by Drumbo:

Originally posted by pctour:
Thanks, for the I have your problem exactly except I have the Duratec engine. I will replace with Motorcraft at first opportunity. I don't have much faith in the dealership would anybody know the part number for the OE plugs for a 99 SE 2.5 Duratec. I am so looking forwad to getting my car back to pre plug change condition. Thanks

Here's a cut-and-paste of a reply I made this evening to another post ...

Here's what happened to my '98 CSVT ... and how it was fixed.

I had the engine "bucking" problem at low/no throttle described in previous posts. It began with uneven accel and a change in the exhaust note, gradually worsened into a severe and re-creatable misfire-like condition (that did cause it to throw codes -- ultimately irrelevant -- and light up the CEL three times), then got to the point where the engine began to flat-out quit under load.

Because the car was at 54.8k, the basics were covered first: replaced fuel filter (Purolator), plugs and wires (Motorcraft). No money wasted -- but no fix, either.

Long story made short: the conscientious guys at the independent repair shop I've been using since my relo to Pittsburgh (Vince's Automotive on Rte 19 in Perrysville, for CEGer's in Pittsburgh) first rescanned the codes, then found a TSB that looked like a possible match with my problem: erratic engine performance triggering multiple codes. It was a match -- A 7-volt wire at the right-rear of the engine compartment, feeding power to 4 sensors, was being chafed at the right-rear engine lift mount; its sheathing had been worn through. Every time engine movement (or Dave, the tech at Vince's) brought it into contact with metal, the four sensors would freak, causing a misfire and/or kill the engine.

Sheathing was repaired; the chafing point of contact was covered with a short section of (I think) neoprene tubing; and the problem is gone.

... Well, almost. The violent bucking (where the tach would drop from 3000 to 1000 RPM and immediately bounce back up), the engine quitting under load and the code-throwing are gone.

But the much slighter stumble, when the A/C is on, is still there. Haven't broken the news to the repair shop, yet.

I had the same trouble that I've heard described here-missing under light to moderate acceleration. I tried many different things to try to stop it. I eventually found that one plug wire was shorting to ground past the spark plug. I bought some silicon grease at the local auto parts store and lightly coated all the plugs and boots with it and haven't had any trouble with missing since. You can check for arcing plug wires by removing the boot from the plug and carefully looking for a white residue in a stright line down the inside of the boot. Hope this helps cause its a cheap fix (under $5).

I just purchased a car with a 2.0 Zetec with the same Bucking problem. My problem happens mostly under 3500 RPM with light throttle, usually when letting off the gas. Did anyone ever solve your problem permanently? I read the post in this thread about changing the plugs being the fix, but I am wondering if anyone has had sucesss with this or other solutions? If so what did you do??

thanks very much Jeff A., West of Boston

New Plugs, wires, and silicone grease in the plug boots to keep water out is the most common solution. I had a carbon track on the side of a plug, gray streaks. Carbon track is gray stuff on the ceramic Is your engine in the Super Seven, that's different!

Welcome Keith39 and livetoshift.

Is it possible that the Variable cam timing Sensor is Bad?? I talked to a Ford Tech who indicated the 98 zetec's had an issue similar to this??