ALLENWRENCH

99 Tahoe gas gauge jumps around from full to empty. anyone know any causes or fixes?
has new fuel pump 3 years ago hasn't worked since

tech2

did it get a new fuel sending unit with the pump?

ALLENWRENCH

I got the hole thing pump and sending

tech2

if it hasn't worked since you put the pump in; maybe the problem is the replacement sending unit. the factory method to check this is to connect a signal generator to the wiring at the tank. changing the hertz signal with change the gauge reading. if the gauge responds appropriately, you know the wiring and gauge is ok and the sending unit is bad.

ALLENWRENCH

thank u ill try that

rojeho

same thing happened to me. I changed the fuel pump and a few months later my fuel gauge became erratic. Reads mainly empty until the tank is about half, and then it is fairly reliable until low. I use the trip odo now, I'm not going to drop the tank again to get back up to the pump/level sender or the wires.