Ok, with the 89 iroc z I just bought, I've been having a bit of a problem.

The whole fuel injection system was replaced by the previous owner before I got involved. Car had some major idling problems on start but fixed that as it was a bad PCV valve.

Now the problem I've been having since I got the car is that on light acceleration it jerks and stutters a bit . When in neutral and you accel lightly the same thing happens minus the jerking and stuttering but you hear some hesitation. If you punch it hard it's fine and accell fast it's fine.

At first we believed it was a misfire but it doesn't seem to be one after all. I was having some backfire issues due to timing (We fixed this and it doesn't backfire anymore.) Then we checked all plugs/wires. #8 shocked the **** out of my friend so he bought new wires and we installed them. Plugs didn't look bad but I will admit I didn't replace them, however I can't imagine it being the plug as it's consistent with gentle acceleration and fine on hard accel. Seems to do it more and mostly noticeably on the lower gears (First, second third). 4th and 5th are ok for the most part.

My friend believes the next best thing to replace is the TPS. Now I'm not too sure how to check out the TPS without just replacing it.

Any ideas what else I can check?

 

I should also note that we have sprayed the MAF with cleaner etc.

Maybe it is a misfire but it's frustrating as hell.

I'd just punch it all of the time but uhh... doesn't work well in NYC traffic.

 

Before replacing the TPS you could to make sure the EGR valve isn't leaking or stuck open. Pull it off and clean it with some carb cleaner or some other cleaner that can remove carbon build-up.

 

Hmm... i'll check that out tonight. Anything else you can suggest before I go and spring on a tps?

 

Maybe you might want to check your IAC(Idle air control) as they blow hand and hand with the throttle body sensors. My Firebird is having a very similar problem but I know it's due to my catalytic being bad. Actually my entire exhaust is jerry rigged lol.
Terry

 

Anything from a spark jump into your buddy's arm could be a misfire or spark jump due to bad wires or wires too hot near the header and dry out causing cracks to the gap is now a misfire finding a faster ground than the side electrode in the head. Or could be a bad torque converter with a, "Shutter" is you said the word that brings up drive-ability is the shuttering torque converter.