2.0 TDI 170 quattro (A4) - fuel pump problem / question / help needed

[Daisdavies]

Whilst accelerating through 2000rpm usually in 4th gear i am experiencing a "juddering" and loss of power until you ease off the throttle and accelerate again. i have previously had the pump within the fuel tank changed (sender) and fuel pump on the engine changed this week as audi informed me this was leaking oil into the fuel system. I am still experiencing this "juddering" problem but audi garage say to use at least a full tank of fuel to ensure it is cleared out.

Any help, guidance or recommendations for this problem or what to do next would be much appreciated

Thanks in advance