Audi 80 2.0E - Revs won't come down!

[AudiMT]

When stationary, if I rev the engine to say 3k to 4k rpm, the revs stay high. In fact, above 4k rpm, they can start to increase! It's the same problem when driving except, when applying the brakes, the revs will eventually drop but it takes a while. The car is idling about 1200 rpm and the idling isn't erratic.

If I disconnect the electrical connector to the idle control valve, the revs drop to a more normal 800 to 900 rpm. Put the connector back on and they jump to around 1200 rpm. I tried cleaning the ICV and I think it's made the situation worse. I also tried another ICV from an old Golf GTI - exact same part number. It didn't really make a difference except this time when I removed the electrical connector to the ICV, the engine stalled.

I looked for vacuum leaks as there is a vacuum pipe that goes into the main inlet manifold. If I pump the brake peddle a few times, the revs will rise a little - not sure if that's normal.

It's an anti-stall feature! 🙂 It's annoying as the car is always screaming and not great when trying to change gears. Is this an ICV problem or is there something else going on?

Thanks!

[Steve Q]

Could it be the MAF sensor?.