Replaced IAC, is this normal ?
http://www.youtube.com/watch?v=BCBn_N7Nt6Y
If this started with the IAC replacement, then I would start by checking over everything touched during that repair. Check for vacuum leaks around the IAC (gasket [O-ring] missing or damaged, screws loose, etc.). Did you touch anything else during the repair (TPS, etc.)?
Maybe you just got a bad IAC.
http://www.youtube.com/watch?v=v9esYBrsmfQ






