i have seen many fuel level sending units go bad in the fuel tank. The little fingers on them wear off. If this is occurring in park or neutral with the fuel sloshing, it is a normal condition due to the buffer being disengaged in the cluster.
The sending unit is probably bad, not unusual.
Mine does, too.. Annoying.
That is the temp. Gauge sending unit.
fuel sending unit broken wire or gauge is bad
bad sending unit
If the vehicle will stall and will not restart or appears to be out of fuel but the fuel gauge reads above empty, replace the fuel sensor assembly and auxiliary tank fuel level sensor if equipped. if not, replace the instrument cluster.
if you are refering to the sensor for the fuel gauge, it is in the fuel tank with the fuel pump.
need more info, engine-details- have you checked vacuum with gauge? etc.
Top rear of the engine next to the distributor.
The fuel sensor in the gas tank is bad.
It's a GM