Hi guys, just putting up a post as it might help someone in the future with faulty fuel gauge.

Mine's been mis-reading since I've had the car. The fuel senders were both fine and so was the gauge on the dash. My car is a quattro so has 2 fuel senders. One was reading fine but the other wasn't. My car would tell me I had zero fuel left when it could still drive for another 150 miles before running out.

Basically the fuel pump assembly in the drivers side of the fuel tank had some how come unattached from whatever it is that holds it to the fuel tank so was just floating about. I think the previous owner has done this as the pipes and connections inside the fuel tank were not standard i.e jubilee clips here and there. As the car was driven the assembly got stuck against the side of the fuel tank, and the measuring float got stuck in a downward position, hence the false gauge reading. I've fixed this by cable tieing the assembly to the remainder of the clip at the base of the tank. It can no longer move about.

An odd random problem I doubt many others will get, but if you have a gauge reading wrong and have checked everything else, this could be your issue.