Either the float is sinking or something changed the resistance. I think the resistance increases from full to empty. Mine gage reads zero until I run thru deep water, then it reads until it dries. I must have a bad ground (infinite resistance) between the float level assy and the tank.
Bob Shaw


87 Raizer, 4.3V6, Mod TH700R4,231CHD, detroit rear and LSD front, bouncy seats, 2" lift and 32x15 BFG MT tires.