I have an 86 TPI 305 and there's a slight idle problem with the car. Basically, it idles poorly for about 30-60 seconds after started. When I first start my car, if I don't tap the gas then my car's idle will drop to about 400rpms and stumble a bit. Once I press the gas it will catch itself and shoot up and act normal. And once the engine warms up a little bit the car runs absolutely perfectly. I'm not really sure where to look or what would cause a rough idle until the car warms up.

 

Try replacing your idle control valve.

 

Follow the tech article to clean your TB and set your IAC and TPS then proceed from there
later
Jeremy

 

I have the same problem, people are always saying IAC, but can someone tell me why it would be the IAC if it only happens when it is cold, I thought IAC would be for all the time. Please help us

Edit: I have decided to just go out and buy a new IAC, it seems to be the only thing that hasnt been done to fix my car so it must be it. I will be installing it some time this week.

 

Replacing the IAC wont do a @#$ thing unless you follow the proper procedure to set the IAC and TPS and that the car leanrs it.

There is an excellent tech article here that will easily show u the proper way to set them both.

later
Jeremy

 

so is there a way to diagnose if it is the IAC or not, I did all of those things in the tech article. It helped a little but not alot.