crazy RPMs...not PCV

Hey guys, my idle seems to be jumpy, but only at certain times. I replaced the PCV valve and gromet. That didn't fix the problem. It seems to happen when I run the car hard (to like 5k rpm) and then put the car in neutral while still coasting along. I called the dealer and they wanted close to $100 for a new IAC.... F' that! Does this problem sound like it's the IAC? I checked most of the vac hoses and they seem fine. I don't hear anything vac leaks. Does NAPA sell IAC's for cheap? Thanks for any help guys!

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