92 v6 surging idle

[svarel]

I have a 92 Gran Am with a problem that has me and 2 other professional Mechanics puzzled.

The car starts just fine, may drive just fine for a short 30 minute or less period than when ideling it will surge up and down and sometimes kill. We have replaced the idel air and air flow same problem. Swapped out computers same problem. Now one of the Mechanics has 3 others Grand Am with identical problems. I want to give this car to MY oldest boy to use at College but not in this condition. I hope someone here has seen this problem and can help us out.

[xeroinfinity]

Welcome to AF.

Did you set the IAC before you installed it ?
And what is the air flow you replaced ?

If its intermittant I'd check the wiring for the MAF or hav it tested.
Usualy surging is from a vacum leak, but it could even be a bad fuel pump. WHich you can check the fuel pressure to see what it reads.

Lastly it could be something in the emissions system going bad.

[svarel]

set the IAC?

[svarel]

also mass air flow sensor was replaced as well as the cat. we have replaced the idel control motor as well since the first posting. The problem still exists. While warming up it will surge up and down like trying to sense where it should be ideling at and will die at times. Runs fine after warm up. Since we moved the prom from the old icm to the replacement think the next step is to try a different icm with a different prom.