If you can, run the car - rev it by hand to approx 3k rpm and press the microswitch on the idle switch - the revs should start bouncing. Dont know what that tests

but i'd assume the idle switch/wiring and possibly ISV as it would activate.
The TPS is on measuring block 003 of Vag-Com, stamp on the throttle and it should go up to 66-75ish.
The MAP vacuum pipe that comes off the inlet manifold/fuel pressure regulator/PCV normally crack and allow extra air in - would check these.
Is the throttle body clean?
Another thing to check would be the coolant temp status on VAG COM - i forget which measuring block it is but its apparent. If it looks way off then may be worth looking into further - i.e. does the car cut out more when cold/hot