Came home, ate something, wanted to go get some gas and all of a sudden the idle was rough. As seen in the video, I pulled out the the sensor for the IAC valve, then electric hydraulic pressure regulator, then throttle switch. Engine bay was too hot plug out the O2 and coolant sensor. Engine did not react as i expected. On KE-Jet cars the ECU goes into a safety map (not limp mode) when any sensor is plugged out and runs of that. 3 months ago the entire fuel system was restored (imjectors, filters, sensors) with new parts and any vacuum leaks have been eliminated. My guess would be the IAC valve (which was not replaced, as it's not part of the fuel system) might be broken, judging from how the rpm rises and drops. Will update tomorrow if it's still doing this.
#1993 Audi 100 2.3 rough idle
weary wigeon
hoary helm
Definitely sounds like the IAC valve either failed or is gunked up.
You might be able to get away with cleaning it out with some with throttle body cleaner instead of just replacing it.
I would also recommend cleaning your throttle body as well.
weary wigeon
Hmm i'll try it. On some older Audis the iac is known to get bad and cleaning does not always help, but i do it. Throttle body has been cleaned inside while doing the maintenance 3 months ago tho.
weary wigeon
Update: idle was rough this morning but not when leaving campus this afternoon. Still gonna clean it and if that doesn't fix it, replcae it entirely