replace the over voltage relay. it powers the idle valve and when disabled, the idle motor goes wide open.

to ACCURATELY diagnose the tps on the afm, you need a scope. pins 2 and 3, I think, it's been awhile. there's a 5v reference voltage and a ground. the 3rd wire is the return to the ecu. look a constant upward slope as the afm opens. good luck, chuck.

OP should test the voltage and see whats going to the IACV first before just replacing parts. I dont recommend a "throw parts at it" approach. Test first. Understand whats going on and then buy stuff.

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Tests are what I'm asking about, but my usual approach is to throw parts in the air. I'm not sure sure on the proper testing process. I sell parts for a living, so I usually have a bunch of stuff hanging around. Not so with this car.

I'm considering buying a 190e parts car and just doing a fuel system overhaul on this car. Oil has been blowing out of a disconnected hose on the valve cover vent for some years now. So I really want to disassemble the system, clean it and reassemble the whole thing. I am unsure at this time whether or not actual parts are at fault, or if the oil soaked and heat baked wiring may be the cause.