I've just got a new Mk2 Golf. 16v KR 1989. When I start it, it revs up to 2000rpm and then very slowly goes down to 1000rpm. When I then rev it, it will stick at that rpm and then if i rev it again it will stay at that rpm. I.e if i rev it to 2000rpm the revs don't drop, then if I were to rev it to 3000rpm it won't drop. The only way to get it to drop back down is to drive off. Also in-between gear changes the revs go up to 3000rpm and stay there.
I can see that the cable isn't sticking when looking in the engine bay. I've checked for air leaks as well. I've also disconnected the ISV and the revs don't drop on idle.
Just took off the intake boot before the throttle body and checked that both butterfly valves were closed, and then started it and the revs still went up higher than normal... I then disconnected the ISV wiring and the TB wiring and the revs dropped a little bit. I have also tried a working ISV off another Golf I have and no change. Would the fact that the crankcase breather is disconnected and where the breather attaches to the air box is blanked off have anything to do with it?
