Car jerks when in gear...

[86darkside]

Car runs fine on the highway thru all gears but in the city under slow normal driving car jerks like it needs more gas so when I do press the gas the car runs fine but if I slow down the car jerks back and forth mind you not slow enough to shut off I have a t5 z spec and my thinking is the gears in the rear end are 3.08 or higher ? Could this be the cause? Should I switch to 3.55 or 3.73? By the way the tires are 215/70!/15 not my choice but that's how I bought it

[RPB]

Those tall tires are not helping things.. I would change them out and then put some 373's in the rear.

[4EYED85]

Did this just start happening or has it done it since you bought it? I would make sure you don't have a hesitation in the engine under load. Stay at a steady slow speed in second and see if it hiccups. A 3.55 gear will seem like night in day driving it, since you are used to the 3.08s. The gears will wake her up a little and you will still be able to cruise 75+.

[86darkside]

[QUOTE=4EYED85;1618479]Did this just start happening or has it done it since you bought it? -> car was a shell the motor and trans are al new from the previous gt I had I never had that problem with the other car but it had 3.27 gears and lower profile tires.

[4EYED85]

Throw some gear at it.

[craigerSS]

if your talking 1st gear only, its normal

[86darkside]

if your talking 1st gear only, its normal

No.
All gears and when I let off in 5th it does it also. Not sudden. But it does the shuffle...lol

[JACook]

If the engine is bucking, gears are not going to solve the problem, other than if they get you into
a higher RPM range where it happens less or goes away. And that's more avoiding the problem
rather than solving it.

How 'bout some details about the car. Is this engine carbureted? EFI? SD or MAF? Stock cam, or?

[86darkside]

308 with trick flows top end kit 24 pound injectors 65 t/b abaco maf motor has only 1,000 miles and is a new block. Cam is also trick flow stage 1 1.6 rockers runs like a bat out of hell. But if you cruise it slowly shifting it stumpbles car has stock rear end and big 215 70! 15 tires. And its not the engine bucking its the car

[fiveoh 86lx]

Similar issue with my 86, 302ci that I put new Edelbrock performer rpm heads on and it has similar bucking and sputtering when cruising and trying to stay at constant speeds below 75. I have 3.73s in it aswell. I'm going to be installing an adjustable fuel pressure regular and larger fuel pump to hopefully eliminate my issue. If it is not that I feel it may be a vacuum issue. and if not that then ill be getting a true dyno tune.
All in all I'm pretty sure my issue is the fuel though it could be the maf and tb are stock size still but that shouldn't be a killer...
Curious for the outcome.

Forgot to mention mine is converted to maf, no longer speed density.

[Ethyl Cat]

its not the engine bucking its the car

???????

Is the pcm tuned?

On an unrelated note- Made it to 500!

[Ethyl Cat]

Could be an IAC dashpot issue.

Did you set minimum idle correctly?

What is the TPS voltage?

[86darkside]

Im about to get a new iac valve since this one is from the old stock 302 i had and will be checking voltage and no the pcm is not tuned.