Me too. Except mine says 3/8 when full and 8:00 when empty. Haven't seriously investigated the problem yet but I did replace the fuel tank sender and I know it's grounded correctly at the tank. So my problem must be at the gauge and your's is likely also the gauge.

I've seen pictures here of a resistor on the back of the gauge that gets fried. Maybe the resistor gets partially shorted and throws off the accuracy of the gauge? Let me know if you find a solution.