I have a bizarre hunting problem with my A6 2.4 V6 1999 edition. When AirCon is on there is almost no hunting and no stalling and idle sits happilly om 600-700. With AirCon off and climate control on economy revs are jumping from 300 to 900 and back.
Please guys Any idea? This drives me nuts and also costs a lot on petrol as Aircon always on.