I have a 78 f150 and I moved the HUD that has my gauges cause I replaced the screw that used to be on it and now my gas gauge doesn't read accurately, not like it's saying it's empty or full just not telling me how much is in the tank. Hovers around half tank and when I fill it up the gauge goes far right way passed the full mark. Any help would be awesome thanks y'all.

 

Have seen where the signal line from the tank sending unit was grounded somewhere , in the older vehicles it would peg the gauge at the full mark, might be a good idea to see just where that screw went.