Its a 03 a6 2.7t quattro.
When I start it cold it runs like a champ. but once that engine temp needle moves a hair the power is gone. Starts bogging down droppping 500 to 1000 rpms instantly. At that point the Cel starts flashing. For awhile if I just put it in cruise control it would drive somewhat ok, but now i can be driving 60 in cruise control and all of a sudden rpms start jumping up and down. I recently had a mechanic replace the MAF sensor for they said it was bad. Now i dont beleive that since the problem now has just gotten worse. The car has 126xxx miles. It has been well taken care of but just starting to run into problems. Any help please