I just brought a 2003 Audi A6 2.7t and the MIL light came on, it was still driving fine, then yesterday I was warming up the car and then it starts flashing and then the car starts idling hard! Then as I drive away it shakes when I accelerate. There is no loss in power it just shakes real hard when I accelerate. I took it back to the car lot where I brought it from. What's the worse case scenario? I just need to know what I'm getting my self into.

 

sounds like a misfire. probably coil packs and/or spark plugs. or it could be something more serious. get codes and we can help you more