2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

4th gear bucking

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Old Jun 14, 2005 | 02:38 PM
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From: Haverhill, MA
4th gear bucking

i was on the highway today and i gave it a little gas as i downshifted into 4th to pass someone. i was accelerating and the car started bucking lightly. my friend drives a starion and he had to replace his vaccum advance because his timing was all messed up when under boost. anyways i dont think 7's have a vaccum advance but maybe something similar. i tried it again a little while later and it was fine. any idea what this could have been?
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Old Jun 14, 2005 | 03:03 PM
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From: Ames, IA
Drivetrain slop in a 15 year old drivetrain combined with "pilot induced oscillations". The car bucks out of phase with your foot, and unless you do something your foot bouncing back and forth will continue to feed the bucking.

Was it bouncing forward & backwards, or missing, or... more detail would be helpful.

-=Russ=-
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Old Jun 14, 2005 | 03:07 PM
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From: on a tiny island in the middle of a sea
I have a buckin in my car too

at really low rpms where teh car feels like it wants to stall.. (goin 10mph in 2nd or 3rd)

the car bucks..


mine is Due to the Tranmission Mount's bushing being shot.. the bolt has nothing to absorb shock with.. just wobbles like a broken engine mount...
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Old Jun 14, 2005 | 03:37 PM
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From: Haverhill, MA
no this is doing about 80 in 4th gear with my foot to the floor. i can see how my foot would bounce if it wasnt to the floor but im not sure how much it would if i was pressing against the floor. maybe....it feels like a loss of power then its back...then its gone...then back.
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Old Jun 14, 2005 | 03:43 PM
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From: on a tiny island in the middle of a sea
is it Fuel cut?
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Old Jun 14, 2005 | 04:12 PM
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From: Haverhill, MA
whats fuel cut? ive never hear the term before...?
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Old Jun 14, 2005 | 04:16 PM
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From: Avondale, Arizona
I occassionally get the same thing.

I'm still trying to determine the problem. Mine is huge bucking though.

A while ago I did all the grounds and it went away. It's now back and worse.

I'm almost thinking it's ignition related.
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Old Jun 14, 2005 | 04:28 PM
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From: Haverhill, MA
you know that would be weird because just yesterday i took my main ignition fuse out. my car flooded after i filled it with gas. i started it and it ran to about 300 rpms then died. i took out the main ignition fuse to blow out all the excess gas then put it back and the car started back up no problem. this is the first time i have felt the bucking. maybe that is what the problem is...?
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Old Jun 14, 2005 | 04:58 PM
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From: Coldspring TX
When's the last time you checked both of your fuel filters?
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Old Jun 14, 2005 | 05:08 PM
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From: Haverhill, MA
yeah...i havent since i bought it


2 weeks...
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Old Jun 14, 2005 | 06:34 PM
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From: Coldspring TX
Does fifth gear buck too when you've got the peddle down?
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Old Jun 14, 2005 | 08:07 PM
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From: Avondale, Arizona
Fuel filter huh? It's been around 23k miles. reminds me I've got to replace it but I doubt that's the problem.
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Old Jun 14, 2005 | 08:23 PM
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From: Coldspring TX
What about your pump sock, Digi?
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Old Jun 14, 2005 | 08:24 PM
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From: Avondale, Arizona
Walbro sock. Everything is 23k miles old.

I get good fuel pressure though. Walbro and Aeromotive FPR show it. Along with no fluctuation in AFR's.
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Old Jun 14, 2005 | 09:38 PM
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From: Haverhill, MA
i have a walboro 225 pump i can put in and i can just pick up a fuel filter for 20 bucks at autozone...it does it in 3rd 4th and 5th noticeably but i havent noticed it in 1st or 2nd yet
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