alright guys i got my 97 SS back from a buddy who bought it a while back.. he has since rebuilt the engine and it is now a 355, with a comp cc306 cam and exhaust, with the comp pro mag rockers, hardened pushrods and guideplates as well as a moroso CAI. it seems to idle ok without the ac on but once you turn the ac on it kind of has a hickup while trying to catch itself and then dies. he has a madz28 tune, and it seems fine without the a/c on but like i said it doesnt wanna idle without the ac on... is there anything i could try as far as making it hold a halfway decent idle with the air on ? i tried adjusting the throttle blade screw but once u hit the gas it wants to hang for a while before coming back down.. thanks

mike

 

The idle is controlled by the PCM. You don't want to monkey with the idle stop screw, unless you can watch the idle air controller (IAC) "counts" on a scanner. The PCM knows that when you turn the A/C on, the engine will need more air at idle, so it opens the IAC motor a few more steps ("counts"). That should keep the idle right where it belongs. If the PCM can not control the idle, there may be a problem with the IAC motor. The IAC is in the baseplate of the throttle body. Again, with a scanner, when you turn the A/C on, you should see the PCM attempt to increase the IAC counts. If it does this, but the idle does not return to spec like it should, the IAC is not responding.

 

thanks i figured that it might be a bad IAC.. it does try and catch itself but it doesnt quite seem to "open" enough to keep it idling... i am going to double check with my buddies scanner, but had thought that may be a problem.. thanks again

mike