I have seen an IAC cause idle issues. Afterall, that is it'* one job. The 121 has me thining though. Off to Google to try DTC P0121
Ok.. after googling, I'm going to say the issue is a bad throttle position sensor or wiring to it. Dan, got your manuals handy? Can you give him the colors of the wiring on the TPS. Let'* have him check the +5 and ground for starters. If a scan tool is available, check throttle position by having key on with engine off and pressing the throttle while watching the tool.
00 Regal GS: All kinds of cool stuff.
Last edited by BillBoost37; 01-30-2009 at 06:45 AM.