Please help with a problem that I've got. I've had my 2001 A6 for about 4 months and it's had a fault since I bought it. It's done 105000 miles. There was an annoying judder/vibration felt through the car whilst driving and intermittently a lack of power around 3000 - 3500 rpm as if there was fuel starvation. I started an elimination process and removed the EGR valve and intake manifolds to clean. Since rebuilding the car, it takes about 15 seconds of cranking before it started, followed by a load of white fumes from exhaust, not unlike a smoke machine.
After much head scratching I found air bubbles in the clear fuel feed pipe to the injection pump. Disconnected the fuel feed pipe at the filter and nothing coming through. Removed rear seats but cant hear the pump priming. Using a test lamp a cant get an electrical feed at fuse no 28, the one for the lift pump.
Has anyone come across anything like this before. I dont want to assume that the lift pump is fault as it a couple of hundred quid. Is there a relay which feeds the fuel pump circuit.
Any help greatly appreciated