I'm a member of many s10 forums, and these days they are flooding with members that has the intermitent jerk/buck at steady speed/rpm problem.

I have tried to fix this problem for some months now, but stillI have not found the problem.

Add your other symptoms, if any, and posible fixes!

My symptoms:

Rough idle
"poffing" out of exhaust at idle
From what I know it's gone when cold, but there when hot

40-55mph / 1500-2000rpm is when I feel the jerking/bucking
Put some more rpm's on it the problem goes away every time

I will put this thread on some other forums and post back if we find the solution.

 

I'm not quite sure on your post but a lot of things can cause jerking from
alignment, suspension, broken motor mount etc. other than that I'm not sure do you have any active codes or anything?

 

Three things come to mind.

1. Temp Sensor for computer is not reading correctly and throwing the fuel mixture off. (Should be located by the water inlet at the front of the engine)

2. O2 Sensors out of spec. (Should have a code for O2 Sensor)

3. Leaking fuel injectors or spider assy.

If it runs normal when cold I would replace the temp. sensor first.
If you have no fault codes I would check your fuel pressure.
I would remove the upper plenum and check for leaking spider assy.

My $ 0.02 Cents Worth of Input.

You also need to determine if it is fuel or spark related based on your write up I would suspect a fuel problem. (Mixture, Pressure, Leaks, Injector)

 

Thanks for the input!

No codes, no problem when cold, can be gone for a day or two, then its back.
Checked temp sensor with autoenginuity, the temp is spot on.

A nother member on this forum described it as if the the tranny would slip for a moment, but there is no change in rpm's.

The problem is also gone when the rough idle is gone.

Checked the plugs a short time ago, no burnt oil or anything, they look normal.

At some other forums, members are filling up the thread, so if they fix it I will post it here.

 

Did you check the correct temp sensor as there is one for the Gauge/Idiot Light and a seperate one for the computer.

 

Yes, I checked them both and they was about the same. But inside the known good values.

 

What year s10 is it?

 

It's in my signature, but it's a 1995

 

Bad distributor drive gear or distributor.

 

For me it was my computer. My 90 fullsize tbi was doing that too and thought it was the trans. Luckily I have a spare engine in my garage and after replacing a ton of stuff replacing the computer fixed it