Nate, you need a sending unit.
OP, you probably need a sending unit.
Edit; should have been a little clearer on things huh?
Fold your rear carpet (hatch/trunk area) forward. On your right you will see a silver plate with 3 or 4 screw. Take em out. Have a looksie at your sending unit.
Full of rust? We know 
LoL. Get a new one…and rock and roll.