I have 97 Trans AM that is having a pretty bad idle surge. When it is cold it will surge and then die. Once it warms up it is better, but still pretty bad. It is worse when i am idling in drive or reverse opposed to park. My lights inside and out also dim when it surges low. I have no idea what could cause this. I was thinking a Vaccum leak some where but the mechanic can't find it. I also recently replaced the EGR Valve and Cylenoid, and it still surges. Any suggestions on what it could be or what to do?

 

Mods list? Was anything done to it just prior to this problem?

 

Holley Throttle Body, MSD Ignition, Performance cam and gears. I just bought this car 2 months ago and it wasn't doing it when i first bought it.

 

Any SES light? What cam? Do you know if the PCM has been tuned? Does the throttle body have an adjustable TPS?

 

My 96 is doing the same thing but it does it once or twice a week usually at night which stumps me. But it's modded and has been retuned and every shop I've asked has no clue at all