[madmaxx]

The reason the gauge drops so fast after half tank is due to the geometry of the tank, you will note how it slopes up towards the rear. It is very simple to adjust the sending unit. open your trunk, remove carpet, remove access plate and you will see the screws to the sending unit. Remove and bend rod to get the reading you want. Note this would not be a good time to start smoking. Also be carefull what you tighten on the sending unit the float and associated arm must move freely so it will move when the level in the tank drops. I have to admit my gauge works like a champ and is calibrated well. I learned how to calibrate one on my previous BDR.