I've just bought a B5 S4 and have discovered an annoying problem, from full the fuel gauge works perfectly fine, when it reaches just under half the stupid thing keeps dropping to empty setting off the annoying warning beep then it flicks straight back up to around what it should read, although it doesn't seem to be too accurate, seems to do it under braking but also does it randomly when its sat idling. Any ideas what the problem is anyone? Dodgy sender unit? I don't really know how the sytem works, how the gauge gets it reading. Any help would be appreciated, anyone had the same problem?