High idle when hot

ford
f150

#1

You guys were most helpful in my last post, I have one more issue. I have a 1991 Ford F150, 351 Windsor 5.8L V8, with 177000 miles. When the engine gets warmed up, it seems to run a little rich, and when I put it in park or neutral, the idle surges way up (I don’t have an RPM gauge, but it’s up there). I recently cleaned the throttle body since the throttle plates seemed to be sticking. Also changed the TPS while I had it off. I put in a new EGR valve a few months ago.



A mechanic said I need a new throttle body, but I’m second guessing that. I’m wondering if I need to reset the computer somehow, since I installed the new TPS. Or maybe clean out/replace the IAC? I know this could be a number of things, but since I’ve been focused on that area of the engine, thought I might have done something wrong. Any assistance would be greatly appreciated.