I am having a problem with my idle. Car starts and idles fine. When I start to drive and then come to a stop, the idle drops to about 500 rpm, runs rough and sometimes dies. Other times the idle surges back up to about 1200 and settles out at 1000 and idles fine. At first I thought this was a learn problem since my battery had to be changed. When doing that in the past, it would act like this but after a driving a few miles with a few stops it would idle normally. This time, it hasn't resolved itself.

 

On the 3.1 V6 engines there is a specific "Idle relearn procedure" that offhand I can't remember the particulars of. In fact all i'm 100% sure of is that it applies only to the 3.1 V6 engines, the earlier 2.8 V6 doesn't have that function. I've mostly heard it mentioned needing to be done after cleaning or replacing the IAC, but who knows, maybe it's needed when all power is lost as in having the battery replaced too. Anyway, search "GM 3.1 V6 Idle relearn" and try the procedure that turns up in your search