Ok all, I made mention to this in the GD topic but I think it's about time to make a thread because this issue is starting to irritate me. Starting about three weeks back, every once in a great while when I shift the tranny into Park, the engine idles up to 1,000 RPM and holds. It drops and rises during this time like the ECU is trying to pull it down but is not succeeding. So, I decided to replace the IAC, which I suspect was faulty anyway due to unresolved cold-start stalling issues last winter. The engine started and idled no problemo, so I decided to rev it. Lo and behold, the engine did not return to it's normal idle of 650 RPM, but instead stuck at friggin' 1,000 RPM again. I revved the engine a little and nothing changed so I revved the engine to 3,000 RPM and what do you know, it returned to proper idle. So, I spent the next little while revving the engine to see if the issue would happen again. And it did but there was no predicting when it would. It was totally random when the engine would return to a high idle rather than a normal idle. Earlier this year, I fiddled with the idle screw on my modified throttle body and had no problems with the setting until now. So, I reversed what I did and the issue was improved but the engine still wanted to high idle on occasion. Went for a drive earlier today and when I stopped at the station, the idle was fine. When I got home, however, the engine high-idled again! This issue has me totally stumped. New IAC, fiddled with the throttle body and the problem as of now remains unresolved. Starting to bug me. What do y'all think? Vacuum leak? Electrical bug? I've got my old throttle body in a box somewhere. If I can find it, I might try putting it back on and see if that does anything if I can't figure this out. If it could possibly make a difference, this problem started about one week after I got my shorties installed.