3.tdi fuel prob

[Andrewren]

Hey guys lookin for advice / help, I have a b7 Quattro 3d , all was going great til last week , coil lite came on,, took to a friend to read for faults, high fuel pressure, low fuel pressure and mechanical prob? Took to vow Audi guy read same codes and advised either fuel pressure sensor wich I have changed£200 and didn't cure. It can drive fine normal driving, then limp mode? I can hammer it and then drive normal, then miby limp mode? Fuel filter been changed just done 80,000 mls and I service it regular, heeeellp? Fuel pressure regulator,? Fuel monitoring sensor? Leak of pipes???? Any advice appreciated x