Recently did tune up on my 02 chevy impala now my gas gauge is going crazy goes from full to half . any help?

changed plugs wires fuel filter oil change gas gauge goes crazy it goes from full to half in seconds stays on full and i know its almost empty got a 3.4 liter engine all i did was diconect fuel filter and put the new one on any comments will help
Recently did tune up on my 02 chevy impala now my gas gauge is going crazy goes from full to half . any help?
possibly since alot of cars i have been working on. the sending unit goes bad. there are little metal fingers that rub on a metal contact pad to tell how much gas. the fingers wear out over time and dont show an accurate reading.








my cold. there is no ground. the wires go from the pump to a circuit box. its on the right under the passenger side where the seat would be looking up
Recently did tune up on my 02 chevy impala now my gas gauge is going crazy goes from full to half . any help?
ck your ground from the tank, the resistance in the ground from the sensor in the tank registers fuel level, a little corrosion or loose connection will do that.