99 Ultra Dash question

When the fuel gets below a quarter tank, the gas gauge goes to empty and dinging, then goes to a full tank reading, just back and forth till I fill it up again. Any help on how to correct this would be great, thanks.

Most likely the problem is not with the dash gauge, but with the sending unit. This can be verified with a bi-directional scanner on the '99, since the scanner can be used in place of the fuel level sending unit to drive the gauge.

It's likely that the bifurcated contact wipers on the level sending unit are losing contact due to wear in the float pivot and loss of spring pressure. That can be repaired, but requires removal of the fuel pump.

http://72.19.213.157/files/LevelSensor05.jpg

Good deal, thanks for your help.

My PA had the exact same problem when I bought it and it was the sending unit. No problems since.