I bought an '04 A4 a couple of weeks ago - within 24 hours of purchase the engine light had come on. Took it back and the garage said it was something to do with the rev counter being out of line with the ecu. Within 24 hours, the engine light had come back on - so I took it back again and they said it was nothing major but had reset all the settings back to the factory basics.

The light then came back on again within 24 hours - really frustrated now as I need to take it back for a third time. It seems to be running fine - the rev flutters when idling - but not majorly.

Would be very grateful for any advice / suggestions!

 

vaccume leak is probably the culprit. With a small studder in idle thats normally the problem. What code keeps coming up.