my fuel tank will read half tank and ill drive it 20 miles and it'll say empty. i put seven gallons in it and it jumped from e to 3/4 tank. When it is all the way out and i put 6 gallons in it it jumps to a little over half tank.Is my ascending unit bad in my tank or what?

 

It certainly sounds like your "fuel level sending unit" is flaky! Depending on the age of the vehicle and fuel pump, it might be time to replace the unit.

 

Aftermarket parts store carry the assembly with a option(can't remember what it was). I went to Chevy, they offer the sending unit . I had same problem, so I bought the sending unit.

 

Check the "Helpful Threads" section at the top of the page, it may provide some helpful information.