1996 Chevrolet Blazer fuel gauge

If it consistently ok at full and empty the id say that the fuel level sendor in the tank is faulty in the center section of the board that reads between full and empty. Sometimes a bad gauge cluster can act this way but usually the rest of the gauges will act strangely. Theres no easy way to test this if youre not familiar with how the tank and gauge cluster are put together it can be a lot to take in. Youll also need to get under the vehicle to access the tank sensor