Fuel Guage Goes Up Then Partly Fades -- 72 Swinger

If this were my problem, I would use the resistor test (if the resistors were readily available). Instead of dropping steering column and messing under the dash, simply unplug the harness at the tank and sub in the resisters and see how the gauge reacts. Real easy, and real cheap. One end of the resister to the gauge harness, and the other end to a good ground. Go from there. I bench tested my dash assembly this way to ensure everything dash related was working before installing the dash.