So I broke down and put in a new fuel pump and sending unit in the truck, only now it will not read above 3/4 of a tank. However empty is accurate, and it's accurate at 1/2 tank as well (presumably, filled it with the same amount as usually and like normal gave me a half tank.)

Verified it was not the gauge with the scanner and it says 72% full on the tank as well. Dipped the tank to confirm it was indeed full. The pump should be the correct one for the screw 30 gallon tank, used the airtex e2533m as others have used and the part numbers said it was for the 30 gallon tank as well. Any ideas on this one?

 

Are you sure the float rod didn't get bent?

 

Honestly that's the only thing I can think of was there's a line in the tank blocking it or it's bent going to carefully take it on another trip this weekend and drop the tank again when we get back.

 

You may have not bent it, the thing could've got bent in transit to you.

I've installed quite a few fuel pumps, and I've found the most common issue with a poor fuel readout after a change out, is likely the rod got heckled up.