All right guys, haven't posted in a long time, but I still lurk about. I finally have run across something that I can't figure out. For the past few months I have been fighting with an issue with intermittant high and hanging idle, as well as P0506 popping up. I have verified multiple times that there are no vacuum leaks. The IAC valve is new, as well as the MAF, timing belt (verified engine timing) and alternator (for the fourth time, keep swamping it when I wheel). I have been Google-ing my face off, but have been unable to find anyone else that has had this issue. Any ideas?