ok to start off... 86 SE V6 now with 5 speed izuzu.
car drives reasonably well, except for this bucking jumping motion it has in 1st and 2nd. when in 1st or 2nd, and just kinda like going slowly through a parking lot or some low speed time, if your not on the gas giving it some go, it like bucks a bit. but if u give it slight throttle, like almost nothing on the pedal, itll go fine, but with no throttle, its gets a little bouncy. 2nd gear is similar. ive also noticed that when in 3rd or 4th, once u let off the gas, it almost hiccups a little...kinda feels like an automatic trans, like when the TC unlocks or something. or like when u let off the gas in an auto at high speeds and it makes that thump feeling as the rpms drop. dont really know if this is a normal feeling or not....only owned auto before, only a few weeks on the 5 speed.

also a question on the shifter. its a little loose. meaning that when in any gear or position, it has a bit of wobble maybe like 1/4 inch or more to the left and right befor it actually moves anything. i took the surround off, and noticed that the ball for the left and right movements, that goes into the slot in the white plastic arm, its a little loose in there. is there anyway to fix that?

thanks

I'd be surprised if a good set of plug wires didn't solve your problem with the hiccups. I've had it happen too many times.

On the shifter.....you either need bushings in the shifter assm or there is play back at the tranny. Get someone to slowly go thru the gears as you see if there is any slack in the cables or bushings or possibly the tranny itself. Good luck and peace.]

Phil

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I am always available to help those that need help. Since my back injury, I cannot work on many of the aspects of the cars, but I can offer the knowledge of my 27 years as a GM technician. Bring the questions on................!

some other causes

bad clutch disk / release fingers or diaphram
burned flywheel face
too high of high engine idle
bad motor / tranny mounts.

mine did that for the last 4 weeks and just yesterday one of the pistons stopped firing (... i think), i don't know whats wrong yet

well....wires are MSD, only about 3 monthes old.
clutch is almost brand new....Ram 9 and 3/4 from fierostore...bout 400 miles on it
mounts seem alright, 1 new, 1 almost as good as new, the other...eh its ok
flywheel seemed to be in good condition when it was installed. bought from another member....i cleaned it and gave it a quick buff with some fine sandpaper to get a tad bit of surface rust off.....

my idle is a tad high....but i dont understand how that would affect...if u could please explain.

as for the shifter, the movement is in the shifter itself, nothing at the trans.

i was thinking on checking the TPS, dont know if that would make a difference or not.

it almost feels like tapping on the gas, letting off, and tapping it again....giving like lurches and bucks....

I have the same bucking in low gears/slow traffic. I suspect a tranny/engine mount or maybe the clutch (although it doesn't slips)....my dogbone is ok but the rear trannymount looks a bit soft and mushy so thats my main suspect. Since I am planning an engineswap in the future I'll keep it as it is for now unless it gets worse....

If its idleing too fast for the speed your going, it will try to slow the engine down and cause it to jerk. ie/ if you let it idle in low gear how fast do you go until its running smooth? 15mph? if you try and creep along at 10mph, its going to buck and jerk unless you ride the clutch.

roger, i think thats the problem then....cuz it usually will be low speeds like 5 through 10 or so, just creeping around when it happens....

so basically u cant go that slow unless ur on the gas or holding the clutch a little bit to aviod the bucking?

What speed or rpm are you experiencing the bucking at? If you go too slow in any gear the car will start to buck.
That doesn't mean anything's wrong - well, except maybe a loose nut behind the steering wheel.

Edit: Just saw your previous post. Yeah, at 5-10mph, it's probably lugging the engine. Push the clutch in.

[This message has been edited by Formula88 (edited 11-21-2004).]

maybe its not that simple...I have a 2.8 5speed, I should be able to move at idle in 1, no feet on the clutch/brake/throttle. Sometimes my fiero slowly starts the shaking. Now when I do the same UP a slope, the engine gets a bigger load but it doesnt start to shake! So it looks to me the load on the engine isnt the issue, but some imbalance somewhere in the driveline or engine/tranny mounts. Hope this makes sense...

I have never had a V6 or I4 idle in gear with out bouncing... think about what you are doing...

That is why they gave you a clutch... to coast in parking lots. Its not bucking... its the drivetrain bouncing off the engine.

Listen to Forumla88. Idleing in any gear will cause the car to buck/bounce like that. Its not or clutch or tranny. You just need to modify your driving habits... its not like an auto that just moves a long slowly at idle... the clutch is a direct connection not the slipping viscous connection you get with an auto. Driving a stick is more involved than driving an auto, thats all.

Going up a hill, more like a slight incline, the IAC will compensate for the engine speed drop and the engine will idle up pulling the car along... when idling on a flat the car can begin to roll sightly faster than the engine idling and the engine will resist the change in speed(engine braking) and slow the car down and then the IAC opens up until the car speeds up again... thats just the way it works, and it can cause an oscillation, or bucking. You have to remember there is a lot of torque multiplication in 1st gear. It doesn't take much to move the car... try quickly stabbing the gas and then let off while in first gear from a slow speed and see what happens, Cars with manual transmissions were not designed to idle in gear. Thans what automatic tansmissions were made for. Care free driving.

There is nothing wrong with your car. Push in your clutch at idle/slow speeds until you need to speed up... That will fix your problem.

It would not hurt to check your engine/tranny mounts if you are not sure of the condition that they are in but I am guessing its just a matter of getting used to a stick.

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88 Fiero GT Auto
01 Prizm 5 Spd.

[This message has been edited by carbon (edited 11-21-2004).]

Yep, mine bucks at parking lot speeds too, unless I ride the clutch a little. Even giving it a little gas, and releasing the clutch, it will buck when I start over a speed bump.
Every manual I've ever owned did the same thing, except an old truck with a very low granny gear.

carbon... good info there... helps out alot. thanks. yea i probly am just getting used to all the different things of owning a manual now instead of auto.... sometimes the littlest things feel like something is totally wrong and i need to think about whats really going on with it. thanks for the update on the way things just are. its better then thinking im doing something way wrong..

quote Originally posted by maryjane: Yep, mine bucks at parking lot speeds too, unless I ride the clutch a little. Even giving it a little gas, and releasing the clutch, it will buck when I start over a speed bump. Every manual I've ever owned did the same thing, except an old truck with a very low granny gear.

Yep, same thing here. Actually, I have never driven a V6 fiero that didn't buck at low speeds.

damn, these cars just wanna go...

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3 car lengths in front of you and still pulling...

Sounds like a surging problem to me. This is caused when the engine runs a little bit lean. The cause could be vacuum leaks, old oxygen sensor, clogged fuel filter, dirty fuel injectors.

I had the EXACT same problem. I took it to Ohio's echeck and they wouldn't test it because it kept bucking, and backfiring on the dyno.

I swapped out the injectors, the MAP sensor, and the Dist cap & rotor. I also ran some "Seafoam" through the engine, and played with the timing. It seams I got everything right, cause it's running OK now. Much better than before.

I am going to take it back up to echek in the next day or so to see what happens.

BTW... It was obvious what the issue was when I swapped the injectors. My #4 cyl injector was NASTY. I think thats what was causing my backfire. Now I am running the injectors from a "3100", and there no backfire whats-so-ever.

Surging and misfiring is not what is being talked about here... the problem is trying to idle in gear... if your car has a surging idle or misfires a lot that is a whole different topic altogether...

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88 Fiero GT Auto
01 Prizm 5 Spd.

No miss-firing here, just bad diferential carrier bearings(112k mi.), causing my low-speed jerking.

Norm

i have the same setup in my 85 2.8 out of my 85gt with the isuzu trans and mine bucks just as you described . There is no problems under acceloration or crusing just when you "putt" around. Usually occurs 25mph and below. It seems like its reving a little high in 2nd and to low in 3rd at 25mph. oh well its good on the interstate though.

yea it is good on highways and such...lotsa fun....but just as u said, kinda bumpy for puttin around

I managed to get rid of some of my bucking - but havent got all of it yet....
replacing my Throttle Position Sensor got rid of my very light throttle bucking
replacing my igntion coil got rid of my steady throttle 1900-2100 rpm bucking
but, I still have a bucking, when I let off the throttle, and roll. as the engine whines down, it will build up some bucking. I beleive this is from fuel pump/low fuel pressure/lean mix.

I have an Isuzu mated to my 2.8, and I have the same exact problems. I have a new clutch and a good hardware so I doubt its the tranny doing it. Its probably idle related.

My money is on the mounts.

I have an 88 so the cradle is solid mounted, I have a new poly dobbone, a new engine mount, a new rear tranny mount and a used but perfect front tranny mount. I am thinking although it could be mount related, that it probably has to do more with the engine idle vs gearing like Roger mentioned. I dn't think there is much that can be done about that though, because the idle is about right for me at around 1100 RPM's. All of my ignition components are new. The engine is new, the sensors and electronics are all new. Clutch and flywheel etc is all new. So that leaves either low fuel pressure, bad injectors, or just bad match with the 2.8 and Isuzu.

quote Originally posted by Toddster: My money is on the mounts.

That would make sense but, I have all new mounts, engine, tranny and dogbone and it bucks the way it did when I got it 13 years ago.

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3 car lengths in front of you and still pulling...