I've got a 2003 Audi A4 with about 60k miles. I recently had the timing belt changed and have performed all regular maintainence.

I was driving home from work the other day and as I pulled off the highway and came to a stop, I felt a slight "clunk" and then the check engine light came on. The engine was running fine, but seemed to be very underpowered. There was a rather pronounced "chugging" coming from the exhaust (like my dad's old 1968 Barracuda). I was about a mile from home, so I limped back to the house. Upon external inspection, the engine seemed to be running smoothly, although it was moving around in a left-to-right manner inside the car. Also, the exhaust system (tailpipes) seemed to be shaking around quite significicantly.

I have an appointment first thing on Tuesday with the dealer but i'd appreciate any insight anyone may have...thanks!

 

First i thought you arethe one of the "happy" owners whos coilpack(s) went out, but after reading that your engine works smooth i dunno... I can go to any AutoZone and scan your car for the codes for free.