My 08 A6 had issues where sometimes the fuel gauge would read empty when starting the car and the low fuel warning would come on. It would reset itself within a couple of minutes. I took the car to the the local independent shop and they replaced the left and right sending units, the fuel pump seal, and the gas cap. That took care of the issue, however now the fuel gauge reads 1/2 full when it's completely full, and shows completely full when it's about half full.

I took the car to the Audi dealer who cleared some codes and returned the car. The issue still exists. I am currently using the trip odometer to estimate how many miles I have left on a tank. When I called the dealer, they advised that their next step would be to check the sending units which were just replaced and also consider switching out the gauge cluster. Any help is appreciated!