been having problems with the car, fuel pressure jumping from good 120+ pressure to as low as 7 bar at the rail. i was told a fuel relief valve on the fuel rail maybe at fault. i bought part from audi at 19+vat. its a threaded piece that goes in below the inlet manifold and accepts fuel line. I havnt changed it yet as it looks in an awkward place! anyone had to change one of these before? I looked to change the sensor/valve on top of the fuel pump (32mm spanner fixing), but they said this comes complete with a fuel pump only? current fault code reads Low fuel pressure. Help, im missing the car big time!