PLEASE HELP --> 2005 A4 Manual Trans-Idling Issue
 

My car is currently sitting at a auto shop getting new brakes as well as trying to figure out what the issue is with the idol. The mechanic test drove it with me and sees what the problem is. He pulled the code up on the computer and is showing a code 4. However, he can't figure out what the problem is yet. The mechanic deals with german cars specifically its just a matter of finding out what the issue is. I thought it initially had something to do with the coil recall but I got all 4 coil packs replaced a few weeks back and still having the issue.

The check engine light is on and while in neutral it idols between 1 and 2 rpm. The shifting is a little rough and the car is sluggish. Sometimes I smell a burning rubber type odor.

Does anyone know what this could be?! I'm trying to avoid taking it to the Audi dealership where they will charge an unnecessary amount of money to fix it.

Any suggestions would be helpful.

Thanks
Kei

Iacv?