Hi,
I have searched the forums and found similar hesitation probs, but maybe not quite the same, and most suggestions start with changing the plugs/wires which have been replaced (with Ford performance wires and Autolite DPs) with no effect, fuel filter is also replaced regularly.
The Problem: When hitting the accelerator from a stop, or if driving down the road at low rpms (i have a manual), if i hit the accelerator more than lightly, the car shudders and stumbles until the rpms get up at least above 2500, then it smooths out. Even idling now, if i hit the accelerator there is a noticeable shuddering and slow increase in rpms until they get up in the 2K+ range. From a stop, if I accelerate carefully I can avoid the stumble, but if I need to move quickly, I am helpless. I can also avoid the problem by revving the engine up a bit before dropping the clutch. I don't normally drive fast and with gas prices try to take it even more easy, but this is a problem that will probably shorten the engine life if left as is. It happens in any gear and at any speed if the engine is not at higher rpms. Cruising at 30-35 mph in 4th, if i hit the accel, bucks n stumbles with no acceleration until the rpms go up. The secondaries appear to be working when required, giving a boost at 3500 rpm. The car idles perfectly for a car with 97K on the OD. I have added berryman's a couple of times, and spray cleaned out the intake, all of which always look shiney clean. I tried pulling one plug wire off at a time, and giving the engine a rev, and each wire removed made it noticeably worse, meaning it isn't just one spark plug or wire causing this. I replaced one of the O2 sensors last year due to a 420 code and CEL lighting (replaced the one that is hardest to get to under the coil area), the light hasn't come on since and isn't coming on or blinking even with pretty serious stuttering and bucking. I haven't made any other mods.
Anyone diagnose something like this? Next step for me would be to take it in and pay someone $100+ for a diagnosis, the going price for a diagnosis that requires actually raising the hood and not just plugging a computer in.
Thanks!
Hi Tony,
Thanks, that second link was perfect! Tonight I plan to re-clean the MAF and clean the upper intake again using the methods in the How-Tos (and the link suggestions). Then reset the PCM and see what happens.
If a MAF sensor was going bad, would it typically throw the CEL on?
Originally posted by mikeydo:
..
If a MAF sensor was going bad, would it typically throw the CEL on?
Yes. But sometimes it doesn't.
Originally posted by Tony2005:
Originally posted by mikeydo:
..
If a MAF sensor was going bad, would it typically throw the CEL on?
Yes. But sometimes it doesn't.
Mikey, if you want to eliminate the MAF as a possible source of your problems, try resetting the PCM & unplug the MAF. If the car runs normally, you had a bad MAF, try cleaning and/or replacing.
If the problem continues after un-plugging the MAF, my first guess would be a bad wire or two. The Ford 'performance' (i.e. racing) wires have been known to be hit or miss. Some get many 10s of thousands of miles out of them, some get only a few minutes enjoyment before they fail... 
Try re-installing your old wires if you happended to keep them as spares or sup'm.
I'm on my 3rd '99 Contique, this is the second with the V-6 that I've owned, so I'm well familliar with the problem.
Best of luck.
Hi Tour,
Thanks for the advice. If I pull the electrical connections from the MAF, would that answer the question without reseting the PCM first? If the problem doesn't get any worse, then the MAF is bad or dirty.
The strange thing, i disconnected each spark plug wire one at a time and ran the engine, and each time engine idled rougher and revved in an ugly manner, much worse than the condition now. So I assumed the wires and plugs are ok, unless one or more of them are just slightly bad.
Did cleaning or replacing the MAF improve any hesitation probs on any of your Tours? Or did the prob end up being plugs/wires?
Thanks again!
Originally posted by mikeydo:
Hi Tour,
Thanks for the advice. If I pull the electrical connections from the MAF, would that answer the question without reseting the PCM first? If the problem doesn't get any worse, then the MAF is bad or dirty.
Sure, you can try it without resetting the PCM - shouldn't hurt anything. If the MAF is the problem & you unplug it, the problem should go away. The car will run smoother if you unplug a bad MAF.
Originally posted by mikeydo:
The strange thing, i disconnected each spark plug wire one at a time and ran the engine, and each time engine idled rougher and revved in an ugly manner, much worse than the condition now. So I assumed the wires and plugs are ok, unless one or more of them are just slightly bad.
Did cleaning or replacing the MAF improve any hesitation probs on any of your Tours? Or did the prob end up being plugs/wires?
For my cars, the problem was always the plugs & wires - Never had to replace a MAF, but did clean them (got the electronics cleaner sitting out right now...). I must admit that after fixing the plug & wire issues, the car certainly ran even BETTER after performing a good UIM/LIM & TB cleaning. Before, the car feels a bit sliggish or had power surges at low RPM when accellerating from a stop. After the cleaning, the car would pull nice & smooth right through to redline. Fuel filter helps too.
Thanks again,
I am going to try the MAF disconnect, then go thru the cleaning along with cleaning the Upper Intake, clear the PCM, and see how we do driving. Will let ya know if that was it!
Well, cleaning the MAF and UIM + PCM reset did not solve the problem. I do notice maybe a little more responsiveness and power in the higher rpm range, but still have the bad stumble in the low to 2K rpm range when accelerating. I cleaned the MAF thoroughly with 100% ethanol, I also noticed removing the electrical connection for the MAF while the engine is running appeared to make no difference at all positive or negative.
I guess the next step is to replace the plug wires one at a time and see if one of them is the problem. The strange thing is I changed the wires/plugs a couple of months ago when the problem showed up. I guess it is possible I replaced an old bad wire with a new bad one, esp if the Ford Perf wires have questionable Quality. I thought they seemed solid, thick and well put together. I think when I got the set of wires on now, i finally threw away two odl wire sets, hopefully i kept at least one...
Oh,
On The Plus Side, The UIM cleaning definitely gave the car an added boost, feels like the power band and secondaries are opening twice as much!
To do it, i didn't pour in the liquid as suggested in How-To. I removed each of the UIM lines (one for brake vacuum, other for multiple vac lines?), one at a time, and used a throttle body spray cleaner. I did this with the engine off because the engine dies out too easily with a line open. Basically, I sprayed in a good dose of throttle cleaner, soaking the intake, started up, kept the rpms up a bit to pull it thru, then repeated this a few times. After holding the rpms for a while after 3 cycles of this, i definitely noticed increased and quicker response at higher rpms. Those secondaries are breathing easier now, and i was always happy with them before!!! Can't wait til i get this hesitation fixed now, should be purring and jumping quicker than it has in a while, and I have always been happy with the power and responsiveness of those secondaries..
I highly recommend doing at least the easy version of the UIM how to cleaning if you haven't yet. I regularly change the fuel/air filters and add gas treatment, but after 97K, the upper intake and secondaries must have been a little gunked up...
Hi again,
About my stumble/hesitation... Recently I have changed the plugs and wires, replaced the fuel filter, cleaned the MAF, cleaned the UIM, added a couple doses of fuel injector cleaner, cleaned out the throttle body. I just checked Each plug and replaced the wires one at a time, no luck.
No CEL light...
In gear, there is a noticeable and dangerous hesitation, out of gear, under the hood pumping of the throttle results in something i can only describe and the engine being punched in the stomach, kind of a deep vibrating suck, then it kicks in a revs up.
Any ideas? Right now i am going to check the coil, and see if i can diagnose that. Next step would be to take it to the dealer, just because i suspect they have the better diagnostic equipment, which may or may not be true. I Hate taking my car in anywhere...
I think your 99 and mine may be twins... I have been having the hesitation and stalling problems for about the last 10 months. It started off happening when I would turn the steering wheel full right or left; then backing up and putting it in gear; then cutting out and stalling when coming to a stop; and finally stalling while moving in low speed traffic to the point where it can't be driven.
My family mechanic THINKS he's isolated it to the VCT and the antipolution controls, but he's not sure yet. if you unplug the wire that sits on top of the VCT (it's the one all the way on the left on top of the VCT, sorry don't know the name for that exact plug) that seems to stop the hesitation/stalling problems, but your CEL comes on. His advice is that the next step would be to replace the solonoid, but he isn't sure that will fix it either.
Honestly, don't bother bringing it to Ford. When this started for me last year, they told me that their solution would be to replace the computer (to the tune of $2k+). Make sure also, that your PVC is ok and you don't need to replace that.
I'm running out of options with mine, and frankly, I'm not sure doing any thing more to it when we can't be sure it's any one thing will work.
But give the unplugging a shot. You'll polute a tad more, but it may stop the problem. Oh, and after you plug it back in, your CEL will go off. But the stalling problem returns after about 400 miles.
My car has just about 123k miles on it now, so I guess it's had a good run. It's just pitifully sad that this is how it is going to potentially end.
Originally posted by mikeydo:
The Problem: When hitting the accelerator from a stop, or if driving down the road at low rpms (i have a manual), if i hit the accelerator more than lightly, the car shudders and stumbles until the rpms get up at least above 2500, then it smooths out. Even idling now, if i hit the accelerator there is a noticeable shuddering and slow increase in rpms until they get up in the 2K+ range. From a stop, if I accelerate carefully I can avoid the stumble, but if I need to move quickly, I am helpless. I can also avoid the problem by revving the engine up a bit before dropping the clutch. I don't normally drive fast and with gas prices try to take it even more easy, but this is a problem that will probably shorten the engine life if left as is. It happens in any gear and at any speed if the engine is not at higher rpms. Cruising at 30-35 mph in 4th, if i hit the accel, bucks n stumbles with no acceleration until the rpms go up. The secondaries appear to be working when required, giving a boost at 3500 rpm. The car idles perfectly for a car with 97K on the OD.
Thanks!
You could not have better discribed the problem I am having with my SVT. If you get it fixed please post and let us know! I also do have the Ford Racing wires... so I will check those. I also just gapped and replaced my plugs along with my fuel filter. Our problem with studdering at low RPMs seems to me like an ignition problem and not as much a fuel problem... but I did replace my fuel filter anyways, hoping it would help (which it didn't). I have had this problem for quite a while now. For me it has got to be coil or bad Ford Racing wires. What other aftermarket wires are you guys running? Any recommendations for wires and where can I get them?
Jeff
Same with me (98SE, 5spd) but only on re-acceleration at cruising speed over 40. I can live with it, but it is noticeable. I have read weak fuel pumps may be the cause of this in some older posts... (provided you have checked everything else first of course; plugs and wires, TB, MAF UIM/LIM...)
Good luck!
Quote:
About my stumble/hesitation... Recently I have changed the plugs and wires, replaced the fuel filter, cleaned the MAF, cleaned the UIM, added a couple doses of fuel injector cleaner, cleaned out the throttle body. I just checked Each plug and replaced the wires one at a time, no luck.
No CEL light...
In gear, there is a noticeable and dangerous hesitation, out of gear, under the hood pumping of the throttle results in something i can only describe and the engine being punched in the stomach, kind of a deep vibrating suck, then it kicks in a revs up.
Any ideas? Right now i am going to check the coil, and see if i can diagnose that. Next step would be to take it to the dealer, just because i suspect they have the better diagnostic equipment, which may or may not be true. I Hate taking my car in anywhere...
i also have the same problem w/98 contour 2.0L 114000km, thought it was bad atx, but my problem is like yours, if someone had a fix for this or possible causes, please post.... i also have no cels,
No answers yet, but it is amazing how many have very much the same problem!
Besides the obvious cleaning of the fuel system, plugs, and wires, it seems there are a few popular causes...
I have heard the possibility of the coil going, and wasn't able to check it myself due to a non-functional Ohmmeter. They are in the $100-$150 range, not unreasonable if I knew it would fix the prob, but a possibility.
Another issue I have heard is the pre-cats burning up, or falling apart and clogging the main cat. That could lead to high back pressure and some of the slight backfiring i think i hear. Unfortunately, this is apparently a $1K+ fix, at least to do it Right...
Weak fuel pump is another possibility.
I have a code reader that seems to do a good job, at least it finds codes when the CEL comes on, but the CEL is not coming on. I had thought maybe diagnostic equipment at a dealer or good mechanics shop would be able to better detect a specific problem with the coil or pump. Can shop diagnostic equipment isolate things like individual injectors or the coil and at least rule these out?
I will keep all updated if I manage to miraculously fix this one!
hi ekelley,
Found this doing a search on VCT, not much info, but it may help you assess your mechanics thoughts on it...
http://autorepair.about.com/library/a/1a/bl433a.htmIt almost seems like we should have a seperate board for hesitation issues!
There are many possible causes, but it would be great to get all the causes/solutions(when found) together.
Both cars of mine are doing this now. The SVT I replaced the FMS wires I had and it fixed it for a few months and now it is doing it again. Luckily the last wires I bought have a lifetime warranty on them. Hopefully I can change them out again and fix it permanently.
It is doughtful to be fuel issues you would have more problems on the top end from inadequate fuel.
I have experienced that also, replacing parts, having the problem go away for a while (days or weeks), only to return without known cause. This happened after i replaced wires and plugs, and after i changed an O2 sensor. I have tried the ultimate in cheap fix attempt... clear the PCM and just drive... even that seems to help the problem, but it comes back. Maybe the engine has to be in constant edit/update mode. Unless there is a problem with the coil sending stray currents and frying the wires, i don't really think the wires go bad that fast. Everyone bashes the FMC wires, but they are definitely a step up from all stock replacement wires. My plugs show very even minimal wear each time. I wish i could test the power of the spark curent at the end of the plug wire, that would at least rule out the wires as the main culprit...
thanks for that link. and see, that's the base problem: you can't isolate it to any one thing. if i could say for sure that it was the VCT solonoid and that after replacing it, the problem would not reproduce, i'd be willing to drop the $600+ labor. but since i've got the higher milage (124k), that would be half of the car's value. i love my car, but not sure at what point "enough" comes.
and yes, hesitations should be a sub-board.
I'm sure most of you have already done this but try checking / cleaning the battery clamps. I had a bad hesitation under any acceleration in my 95 SE 5spd. I changed the battery b/c it was causing issues and it cleared up for a day or two then started in again.
Come to find out, I had a cracked battery clamp where it connects to the battery post.
Just another thought.
Check all your ground leads too. That'll cause a misfire.
I had similar problems on my 98 SVT. I changed both bank upper O2 sensors due to CEL's. I then cleaned the IAC valve and the problem went away for a few weeks. When the bad idle/hesitation came back I bought a new IAC which seemed to cure the problem.
Do you notice any difference when the A/C is on?