i have an 06 ss supercharged and this problem has been goin on for awhile. whenever i come to a stop or in neutral the car usually idles at 1000 rpm but it flutters down to 500rpm and its even stalled on me a few time.i called the dealer and they said try some fuel injector cleaner so i did and it didnt work so i'am wondering if you guys have any ideas on wat it could be.i just got a recall notice for the 06 though about the front cat can go bad so iam really at a loss here.

 

Clean your throttle body

https://www.cobaltss.net/forums/2-0l-lsj-performance-tech-47/idle-problem-cure-finally-116051/