So I'm back at square one with the high idle issue. Apparently the dash diagnostics are telling me the engine temp in Celsius even though it clearly has an 'F' in the display!!
So the engine is reaching normal temperature, radiator fans work correctly, etc, etc.
I have a scan tool that I can monitor things with. What should I look for? I'm going to verify the voltage range of the tps and some other things.
At this point I might just break down and buy a motorcraft IAC valve. Has anyone had bad luck with IAC valves from autozone? Again, if I disconnect the IAC valve, the car runs great and idles just as you'd expect a car to idle at.