Hey guys I am wondering if the IAC wiring on the LS-1 is different than the stock wiring on the cavalier. I have installed the LS-1 TB, but it does not apear that the IAC is working or moving like it should. The idle seems to be set with the idle adjustment screw rather than automatically with the IAC. Any info on this would help. I tried to search for iac pin-up or wiring for the j-body... No success... But this should answer my question... .

Currently the car idles high 1100rpm when its colder outside (early morning), and lower 800rpm when its warmed up outside.

PS I rewired the TPS gray to Blue already... and seems to be working fine...

IAC wiring is plug and play between the two, the only difference is the connector style of the TPS. I've never had issues with mine. Sure the IAC motor is good?

And you'll probably see a very slight idle surge due to the small air pass hole in the throttle plate.

Thanks for the response. I double checked wiring diagrams for the TPS online and realized that I had the 5v and signal switched. I swapped those back to how they should be, but the TPs was still reading incorrectly (.5v-1v @ idle 0% throttle and 4v @ WOT 100% throttle) and the car was idling high. I then unplugged the TPS and the idle dropped instantly. This showed me that the TPS was bad. I bought and installed a Borg Warner LS-1 TPS and BINGO! It reads perfectly and idles correctly.

The idle is now a touch on the low side w/ AC on. I have the hole in the throttle plate welded, so I may adjust the idle control a touch as long as it doesn't start reading a throttle increase... Or I could always drill a smaller hole in the plate if the throttle value is increasing.

I see that there are 2 different IAC's for LS-1 style throttle bodies with 2 different costs. Does anyone know the difference? AC162 vs AC234 I believe are the Delco numbers.