John

I agree with Tony maybe it could be the swirl flap actuators.

What I was getting at though, if it is referring to the throttle valve actuator (the one at the entrance to the intake manifold) how is it controlled vacuum or a motor. If it is vacuum maybe the vacuum control solenoid or electrical circuit is faulty.

Also,
If it is controlled via a motor watch out for the plastic gears inside the throttle body for stripping. This is quite common in other audi/vw models.

James