I had a fuel pump installed on my A6 about a year and a half ago. But ever since that day the car burps and jerks from time to time when driving and hesitates under hard excelerations. Most of the problems acure when the gas meter reaches a quarter tank or less in fuel. When this happens I can hit the brakes or swerve the car back and for and it will stop but. But it is annoying as hell. Someone please help.:mad

 

I recall that on some Audi's and VW's they had issues with the fuel supply line within the tank getting lose. Once that happens the line floats on top of the fuel and you will experience issues like you describe with a quarter tank or less.
If the issue happens even with a full tank - I'd check/replace the fuel filter.

Good luck!