Ok i'm baffled and it doesn't take much when it involves electricity:frustration:My gas guage is hit n miss asto weather it works or not, when it does work it reads only half the guage ie: a full tank shows as half a half tank shows on guage as a quarter tank if i wash the truck and wash the top of the gas tank it works fine (usually) That is the easy part now for the messed up part.......... i used a test light on it conected to the neg terminal nothing from either wire or sending unit base, hook test light to positive terminal both wires light it up and so does the base plate go in truck after testing and rehooking wires and it is reading correct?(for now lol) oh yes it is a 91 subaru sambar carb
check your gauge cluster...sounds like part of the circuit board on the back is sending power back through the gauge to the sender...could be a loose screw on the gauge as well (some gauge clusters ground through the mounting screws to the circuit board) could also be a wire somewhere in the gauge cluster again where it plugs into the back of the cluster...last thought is to see if the fuel tank sender wires are bundled with any other wires..could be a leak through there as well... you could try starting the truck and unplugging different fuses to see if any has an effect on your gauge reading..then you could at least narrow down the crossed circuit possibilities
