check engine light

Hello, This is indicating that there is a misfire in the engine, try not to drive it in this condition, you can damage your catalytic converter. You'll need to have the diagnostic trouble codes read out and diagnosed. I can tell you that on this model, it is common to see the ignition coils fail and cause this problem.

audi has a recall coming for the "pencil type" coils. you may be able to get this fixed for free at the dealer if its coils, its worth a call.

The TSB is 01-07-28, What are the trouble codes.