weird fuel level issue
car is a 98 TA
98 might have the traditional 0-90 ohm level sender (0 at empty, 90 at full tank) or it has the weird fbody setup of 230-40 ohm or whatever silly values GM came up with (230 at full tank, 40 at empty).
Mechanical issues that might be throwing off the gauge:
Level sender might be catching on something in the tank.
Corrosion.
Electrical short at the bulkhead connections.



