When I start up my car ('87 Iroc TPI) it starts idling real rough, almost like I have a hot cam. And during this rough idling, looking at the tach, the needle quickly goes up then down repeatedly for a few seconds, like its surging. Coincidently, it does the same thing when I put the car in overdrive on the highway. All the sudden it starts running real rough. It doesn't do it in town since I'm not in the overdrive gear. Could this be a sensor thing? When I first got my car a few years ago it pretty much did the same thing. If I remember correctly, they put in a knock sensor or something. Also why does it seem not to run rough in town. When I'm at a stop light it runs good and acceleration seems normal. I'm going to try to fix this myself with you guys help. Thanks.

 

*bump

 

your plugs are probably foulling out. do you blow smoke on startup, if so it is a cause, or running rich will do it to.

thanks
anthony

 

I dont think its the plugs anthony. The reason why is the car runs fine except on startup and once I get on the highway and put it in overdrive. In town it runs like normal, dont know why. I also had a tuneup done about a year ago. I'm pretty sure it must be some sensor. Do you have any idea what sensor this could be or how I could pinpoint the fouling sensor? Thanks

 

so it only happens at lower rpm, but not in 1st 2nd or 3rd.......hrmmmm

 

mine does almost the same thing yours does, runs fine after the car warms up, but it is not the warming up that helps it, it is the comp picking up the idle a little when off of the gas. mine still has the original ac plugs and are burnt to hell. i am going to replace them soon. i would pull a plug from each side of the motor and see what the condition is in, just to be safe.

thanks
anthony

 

I'll try it, thanks

 

lut us know if it fixes it.

thanks
anthony

 

Kind of sounds like what mine is doing, Real rough when cold and you can't tap the gas it stall out but punch it- it jump up high and will not hold a certain rpm, 5 min later ,warm it's all good.

 

Yeah Rosco, that's exactly what mine is doing on startup. Wish I really did though have a hot cam and not just sound like one for a few minutes. I am taking it to the shop to see if they can find the problem. The car basically runs fine except for that occasional "stuttering" on the highway. So it might be pretty hard to diagnose, also the engine light doesn't come on. But, if I find out anything I'll let you guys know.

 

Got my car back yesterday. And Anthony was correct on his diagnosis:hail:. One of the plug wires was almost burnt in half So they replaced all the plug wires. Now the car runs like normal. I never would of thought this to be the case since I had a tuneup so recently, but thanks everyone.

 

no problem, glad to here it is running the way it should.

good luck with it
anthony