u/ta-ta-toothy

I filled up two weeks ago and my gas gauge only said 3/4 and the distance to empty corresponded with 3/4 full. While driving a few days later, the gas suddenly moved to full and the distance to empty was over 100 miles more than possible. I tried to reset the fuel pump and gauges by disconnecting the battery for a few hours but it’s still showing too high for what’s in the tank and a distance that would be impossible. Any suggestions?