im having a similar problem with my fuel gauge at the moment. Mine was stuck on half. It would rise but not go below half. but with ignition off it would then drop to empty. i took the sender out of the tank and moved the float up and down and the gauge went up and down with the sender. I then fitted it back into the tank and now it reads empty all the time. Which aint too good when ur running a V8 and trying to guess how much further you can go without filling it up again. i was going to go down a new sender route but might try other things first. I'll be interested in how you get on with yours.