What is with the rough idle here? I have an 89 L98/auto GTA, and this thing idles so rough and surges so bad, its getting on my nerves. I just put new injectors in it, it has new plugs and wires, and supposedly a new cap and rotor. I heard these TPI motors run a little rough once in a while, but come on! The car has 106,000 miles and just ran a 14.85 bone stock last saturday, so I know the motor cant be all that bad. How about O2 sensor or IAC? Is there a way to test those?? Please help, this is embarrasing.

 

By the way, the idle speed in gear is about 600-650. Is this too low? It seems like it

 

Like you said, it sounds like the IAC. I would first try the 02 since its cheap, and should be replaced every 30,000 miles anyway.

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Rob
'86 TA 305 TPI

 

did you replace the injectors with 22lbs or 24? My 89 Formula 350 ALWAYS surges when its warm and that pisses me off too. try taking the IAC out and cleaning and resetting it. check your fuel pressure. I think mine surges because i have 6 bad injectors.

 

Well, i actually had my original injetors cleaned and balanced and so on. They are the original 22lb injectors if that helps.

 

anybody have any other ideas??

 

Depending on the severity of your surging and the drivability of the car, did you make sure you put the right wires in the right places on the cap? I switched two once an the car had a horrible idle and would not accelerate, and to think i had checked over it three times already......

did you damage or drop a plug when you put them in, are the wires all on tight?

just some thoughts......

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1986 Trans Am
305 TPI
"If it's not one thing, it's another!"
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