I've had this issue for the last year and it is getting annoying! The car was taken out of winter storage last year, driven for a month, then it sat for two weeks while I used my truck to do work. Started the car and this is what it did. it runs right up to 3500rpm and stays there. Unplug the iac valve and it runs fine, idles a little low at about 600rpm but stumbles and will stall at red lights until it gets warmed up. I've put three different iac valves in it with no change. I've replaced the blue temp sensor, checked the throttle switches, cleaned all the grounds, checked for vacuum leaks, nothing works. Almost at my whit's end over this getting tired of it! Could it be the digi2 ecu? hard to find and expensive.