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zetec bucking/hesitation

B

BrApple

No Life But CEG
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Dec 23, 2001
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Location
Gales Ferry, CT
95 zetec, 5spd, 216k, drop in K&N.

seeming a random occurance, only when the engine is cold. some mornings its worse then others too. Normally on level ground at light throttle and pretty much steady engine rpm I will get a bad bucking/hesitation. Once up to temp it doesn't seem to be an issue. Also a few time getting on the highway in the morning and flooring it to get up to speed I have had it fall flat on its face around 5 k rpm. fuel level doesn't seem to effect anything.

in the last year I have changed the plugs and wires w/new motorcraft parts. Gota new O2 sensor and swapped to a coil with half the miles. The fuel filter isn't to old either. I do want to try cleaning the maf again to see if that makes a difference.
 
Sounds like what my LX is doing. Someone told me that my secondaries were probably stuck open, but the thing I dont get is why it would go away after the cars warmed up.

-- Does it almost backfire? Thats what mine does. It seems to fall on its face and kinda pop but once i hit 3 grand no problems. than 5 minutes up the street it doesnt happen at all.
 
NewTourd95 said:
Does it almost backfire? Thats what mine does. It seems to fall on its face and kinda pop but once i hit 3 grand no problems. than 5 minutes up the street it doesnt happen at all.
Click to expand...

Mine has been doing that for 6 years. Even with the new 3L and built trans I still get it. Never figured out why. Only things left I havn't changed are:
-injectors
-LIM
-fuel pump
-IAC
-MAF
 
BrApple said:
95 zetec, 5spd, 216k, drop in K&N.

seeming a random occurance, only when the engine is cold. some mornings its worse then others too. Normally on level ground at light throttle and pretty much steady engine rpm I will get a bad bucking/hesitation. Once up to temp it doesn't seem to be an issue. Also a few time getting on the highway in the morning and flooring it to get up to speed I have had it fall flat on its face around 5 k rpm. fuel level doesn't seem to effect anything.

in the last year I have changed the plugs and wires w/new motorcraft parts. Gota new O2 sensor and swapped to a coil with half the miles. The fuel filter isn't to old either. I do want to try cleaning the maf again to see if that makes a difference.
Click to expand...

Have you checked for pending codes Brian? Sounds like you'd be on the verge of a CEL with those kind of symptoms, but I'm not completely familiar with OBD-I, sorry.
 
no I haven't done much of anything. I just back off and let it smooth out. by the time I really get going in the morning to work or on my way home its fine so I haven't worried to much about it. I do think I can check for pending codes, I know I can check for stored codes.

and as far as I remember the only time I have had a cel was because of something I did, like running with the maf unplugged or not having the O2 sensor connector firmly seated, etc. knock on wood for that one ....
 
Hesitation

Hesitation

Brapple if it helps at all I had the same problem and actually had a bad plug which was a brand new one (less than 500 km) out of the package (platinum). I believe you can check the continuity of the plugs with a multi-tester, IE check them all to see if one has too much resistance compared to the others. I had a similar issue 25,000 later and it was a wire. Wires were fairly "new" they were champion and aint nuthin made like it used to be. (Thinking about how the car bucked makes me :eek:sick:eek: just remembering). Best of luck. For the plug the car eventually threw a misfire code, for the wire there was never a code. Just the awful awful bucking.
 
well as I recall it was doing this some before I changed the plugs, wires and coil pack. I believe that was part of the reason I change everything, that and looking to get better gas milage, which its been pretty good, even better with more highway driving of course. the previous plugs and wires had about 100k on them. coil was original to my knowledge.

I should pull the plugs and check the gaps. I know #3 and 4 where burned up fairly well on the old set, and the gap was way to big.
 
Well I just recently changed my plugs and wires. Old plugs were beat up and the gap was to about .07" :shocked:. New plugs at .05" and new wires...not much difference.
 
might it be as simple as powerterain mounts? 3 of the 4 are original. rear roll restrictor was replaced because the original fluid filled one ripped open like is typical. but that one has like 150k on it now.

this morning it happened again, but instead of backing off I held the gas and it only happened around 2k rpm, after that it smoothed out again.
 
Brapple when it was my wire, the bucking was so bad on a trip home I had to keep revs over 3,000 the whole way. The wires only had about 30,000 km on them, I thought they were good for 50k, but I was wrong. I changed those wires and... poof :crazy: the bucking was gone. Have put 12k on since then, no more buckies. It was actually the ends by the spark unit that were bad / faulty. Had that green chalk and then one of the spring clips disintigrated in my hand. Kind of :eek:embarrassing:eek: that it was that simple, but my car was doing EXACTLY what yours is.
 
only thing with that is it did it before and after I changed the plugs and wires.

yesterday it was fine, this morning it was pretty bad. but again after its up to temp it isn't an issue.
 
spark plug wires usually do something like that... I would swap in another set just for ****s and giggles. That zetec motor is such a mystery for bucking/hesitations, back when I had my 96 I went through 4 sets of plugs and wires within 10K miles because the plugs and wires kept going bad, and in the end it turned out to be my coil pack :shrug:

but I did have 2 sets of plugs that the porcelain cracked on.
 
yeah I already swapped the coil ... and it only happens when the engine is cold and it seems to be right around or at 2k rpm and it isn't all of the time. I am ruling out spark issues. if it was a spark issue I would most likely be getting poor gas milage too, and it hasn't changed at all ...
 
BrApple said:
yeah I already swapped the coil ... and it only happens when the engine is cold and it seems to be right around or at 2k rpm and it isn't all of the time. I am ruling out spark issues. if it was a spark issue I would most likely be getting poor gas milage too, and it hasn't changed at all ...
Click to expand...

so maybe a fuel related issue, maybe your filter sock is dirty?

Have you checked the fuel pressure?
 
I wouldn't take gas mileage as a good indicator of how the engine is running, Brian. Not trying to pick on you, but I'm speaking from current issues that I'm having. I have a P0133 AND P0171 (they come on <50 miles of driving), and I just pulled 27mpg last tank. Best I've ever managed was 28. Go figure. :shrug:
 
zorrex said:
I wouldn't take gas mileage as a good indicator of how the engine is running, Brian. Not trying to pick on you, but I'm speaking from current issues that I'm having. I have a P0133 AND P0171 (they come on <50 miles of driving), and I just pulled 27mpg last tank. Best I've ever managed was 28. Go figure. :shrug:
Click to expand...

Ian has a good point, on my pre98 when I was dealing with misfires I was still averaging 29-31
 
Codes

Codes

I was getting intermittent codes too, P0133 AND P0171. But they were related to an upper 02 sensor. I had the bucking before and after the 02 sensor... but not since the wires were replaced. And I have my original coil pack. Well you have eliminated spark so I will stop posting. BUT I have a nice klunk in my front end and I think it is the front LCA bushing. I am prying up the LCA in the photo. The lca moves almost 1/2 inch when i pry on it. Time to change it?
 

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Very similar issue that was happening with my brother's Mystique. It turned out to be a dirty MAF. I used the MAF that the guy we bought his CTA intake from threw in with the assembly. That's when it started acting up. I swapped back to the original, only to have that one do it as well. I believe in the end, one was bad, and his original was dirty from the K&N drop-in he had. Both showed almost the same issues.

A year later and it's still fine. IIRC, I used an electronic cleaner spray from Radio Shack.
 
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