I have a 2002 Audi A4 3.0 L (B6). Today when I was driving on the freeway I noticed that the MPG numbers on the dashboard started going crazy. It kept jumping from random numbers. I got numbers like 15, 22, 40, 90, 200, even 700. Every second it changes to random numbers like that. Could this be some kind of messed up sensor? HOw serious is the problem? Suggestions on how to fix? I appreciate the help in advance.