My gas gauge only reads half full when the tank is completely full. It goes to empty rather quickly and shows empty when it's half full.

I tried to take out my sending unit but it wouldn't move (I only had a screwdriver). When I was under the car I realized that my sending unit doesn't have a ground strap to the fuel line. My rubber fuel line is rather long too - about 12". The sending unit seems to have metal to metal contact with the tank via the tabs - is that enough to ground it?

What's more likely for my gauge reading only half issue? a bent arm on the sending unit (no clue if it's a repro unit or not but it looks old)? half sunk float? missing ground strap of sending unit?

doesn't hurt to add one, but it could be any of the things you say.

in addition, bad vr, but if your temp gauge reads right, then is probably sending unit issues.

has it ever read correctly?

Float could be bad. Or a bad spot on the sending unit where the thingy rides on the other thingy that tells the sending unit what the level is. Have had this problem with a few cars.

I see you are in Graz, Austria. I live near Gratz, Pennsylvania.

Take the wire that goes to the sending unit and run a jumper wire from it to ground. The fuel gauge should max out. If if does you either have a bad sending unit or sending unit ground issue. If it does not the gauge or the voltage limiter in the dash is bad or needs adjusted.

Thanks for the help fellas. Temp sending unit was replaced and now operating. Gettin ready to drop the tank when the sending unit part arrives.