Ive been noticing my Gas Gauge acting up after I fill the tank,twice when driving the needle sank quickly from full to quarter and alittle farther almost to half then would slowly float back up,when the truck stops it seems to go back to the normal level it should be but when driving I notice this erratic fluctuation this is a recent phenomenon. I dropped a can of Fuel injector cleaner and filled the tank and thats the first time I noticed driving from station. Could topping off the tank too much affect the float in the tank? I checked all connections to fuel tank hoses and plugs all seems good,there is something definetly wrong and would like to remedy myself no warranty. The dealership dropped the fuel tank to do a TSB bulletin about 2years ago but the gauge worked fine then? I dont know if its the float hanging up or electrical problem. The gauge is definetly not giving accurate reading, Any help appreciated. Its a 2004 V6.