one thing you can do to see if its sticking is remove the intake pipe when it connects to the throttle. turn the ignition on but dont start it! then get a mate to press the throttle pedal and you should see the butterfly valve opening and closing.
I take it the throttle is sticking at 2000rpm just briefly after a cold start?
I've got throttle issues as well. It rarely fast idles (1200rpm) and when it does, it shoots up to 2000 for a second then drops to 1200.
Already cleaned and polished the throttle, but I saw gouges in the main body where the blade was rubbing it. The throttle also squeaks when moved by hand, so I think it's fecked.
I'm going to try a MK5 throttle as they were improved, but don't have the coolant inputs, so I'll just join the two hoses together.
There are no fault codes in my case, which is odd because if the ECU is trying to open the throttle X percent to maintain a cold idle, but doesn't get there, I'd expect that to show up in VAG-COM, but nope!
thanks yohan appreciated a bit far, mines a bit different corrado fine when cold but on restart when i drive off it sticks just over 2000 revs
cleaned the air sensor and put an itg filter in so ill see if any change in the next few days