I would guess something is loose and floating in your gas tank or perhaps there is a new dent in your tank if its metal. It seems like something is preventing the float on the fuel guage from responding. I would guess the wiring is OK as you can still get a reading so that tells me all might be ok wiring wise and the trouble is in the tank.
You could have loose parts in the tank including the fuel pump, low fuel sensors or even something someone dropped in the tank for a prank like a ball that are loose and floating around. Many fuel pumps are designed to break away and 'disconnect' in the event of a crash so if you had a near miss or moderate bump here of late the fuel pump could be flopping around and getting in the way of the fuel guage float. It (the fuel pump) still might be working as it didn't totally disconnect. The wires stay connected but, the pump physically falls off its holder and disconnects from the fuel line. When that happens you in effect don't have a pressurized fuel leak in the event of a serious crash.
You could have loose parts in the tank including the fuel pump, low fuel sensors or even something someone dropped in the tank for a prank like a ball that are loose and floating around. Many fuel pumps are designed to break away and 'disconnect' in the event of a crash so if you had a near miss or moderate bump here of late the fuel pump could be flopping around and getting in the way of the fuel guage float. It (the fuel pump) still might be working as it didn't totally disconnect. The wires stay connected but, the pump physically falls off its holder and disconnects from the fuel line. When that happens you in effect don't have a pressurized fuel leak in the event of a serious crash.