My 88 GTA 350 is acting really cranky when cold. When I first start it, it chugs a bit before idling at about 700 while warming up. Doesnt stall though, just chugs a bit then smooths. If I try and drive it while cold, I get a severe stumble and hesitation, which also seems to affect the trans shifting. Once the car is warmed up, it runs fine. Now, I have swapped to an Accel base and added a set of Hooker 2055's, along with replacing the O2 and just recently the secondary fan switch. When I had gotten the car all back together, I set the TPS, which was fine. I tried setting the IAC, but seemed to have an issue. I followed the procedure from on here, but the car would never drop to the 450rpm like it should have. So I know the ISC isnt set totally correct. I am throwing no codes either. Could it be as simple as the ISC being set wrong to cause this? I hate having to wait for it to warm up before driving it. If anyone has another way to do the ISC procedure, I'd love to know. Thanks.

Terry

 

Is the IAC sticking? Do a search for Vader's instructions on how to tear it apart to clean it, It may be gunked up and sticking.

 

Is your timing set correctly?? When I was fixing my car with a cold problem that seems similar to yours, the timing made a big difference.
Good luck.
Also another thing that I will be doing to my car to fix the other cold start problem is the Cold Start Injector. Try searching that.

 

Now that you mention it, when I last set the timing, I forgot to unplug the plug by the firewall, so maybe thats it. I'll have to reset that first and see what happens. Thanks for the reminder.

Terry