Got a one stock L98 91 Z28 and just cleaned out the IAC to fix a slight idle prob. it had. Broke the plug pulling it off(one of the round plastic things around the contact). Do you have to set the Idle speed if u take it out since it is spring loaded, or should it just work after popping it back in. (trying to see if it is the plug that's not making contact, or if i have to set the idle speed.)

The spring is only there to help it extend a bit.

Have someone turn the key on, to run, but don't start the engine. While someone is turning the key, place your finger on the IAC, "feel" if it's funtioning.

I'm not sure you will feel anything, if it's in the correct position...so if you don't...then remove the IAC again, and press the pintle back...just let it stick out about an inch.

Redo the "have someone turn the key" thing again, see if it's driving. If it is, the connection is okay.

Oh, do not turn the key on with the IAC removed and plugged in...the pintle will go flying...don't ask me how I know