When I replaced my tank 2 years ago, the gauge always read real low (full was about 3/4 on the guage). After replacing the tank, and putting in a new sending unit, it still read the same (arrrrrrrg.)
The ground was good. I changed it several times to make sure. No difference. So I lived with it.
Now the strange thing. Since moving to Virginia, I noticed that the gauge seemed to be closer to true. Tonight, when I filled up on the way home from work, it read almost full!
Strange
Brian