Just bought the girlfriend a 04 S4, really cool car!! 49k miles and CEL just came on and it is idleing ruff. Only owned the car for 1000miles now. Anyone have problems like this. It will go to the dealer to get checked out. Just curious if anyone has had this same problem.

 

You might be knocking. Did you fill the car up with the right kind of fuel?

 

YES, 91 OCT. SUPER WEIRD, GIRLFREIND WAS DRIVING IT AND NOTICED THAT IT WASNT RUNNING RIGHT, SHE SAID THE CAR WAS SHAKING A BIT AT IDLE. I GOT IN IT AND COULD TELL RIGHT AWAY THAT IT WAS RUNNING REAL RUFF. ALSO I NOTICED CEL WAS ON.

 

Just be safe, take it to a dealer and have them run a Vagcom, see what codes come up. You're prolly misfiring on a cylinder.