Sorry for the long post, each little paragraph is a specific test I tried. I have been very thorough as you will see. Please take the time to read through it all. Been troubleshooting my fuel gauge, initially I grounded the sending unit lead to the tank and the gauge pegged full, so I changed the sending unit. Found out the float had flooded and was now an anchor. Replaced the sending unit, checked the resistances on it before hand, 8 ohm at full, 79 ohms at empty. Pretty close to Fords Spec (10 full 73 empty). And Also, it was very very close the the readings on my old sending unit with the bad float. Put fuel in 1 gal at a time, needle came up to the empty mark but never went above it. Checked again at 2, 3, 4, and 5 gal. Resistance on the float was changing, however the gauge indication never got above the empty line. So again, I grounded the lead to the tank and it pegged full. I also have 5 volts at the lead. I checked grounds from my fuel sender body (by the retaining ring) to the gas tank, the trunk floor, the leaf spring, and my exhaust pipes. All checked good Rechecked the same ground again but using the resistance scale, got 53 ohms to each one. Checking resistance though only the sender and also gave me 53 ohms. So my tanks seems to be perfectly grounded. I pulled my cluster out, checked resistance at the circuit board plug for the wire going to the sending unit and a dash ground. 53 ohms. Perfect! Right?? Checked resistance for at the corresponding lead on the circuit board, though and to the far side of the gauge. Got 13 ohms. I also checked for shorts to ground and did not find any. Knowing that the water temp and oil pressure are the exact same gauges, I checked resistance across them. Got 12.8 and 12.9 ohms. I even made a short test lead with a bullet plug into the original lead, and a round terminal securely jam-nutted onto the threaded lead on the sender to guarantee a good connection. Check resistance from the instrument plug to ground, 53 ohms... Turned key on and needle read empty still. This next test is straight out of the ford manual: Now, to completely rule out the sending unit, even though is it obviously working as so far in spec, I got a potentiometer from radio shack, connected the wiper to one end and one of the legs to ground. Set it to 10 ohms. Verified 10 ohms from the instrument plug to dash ground, applied power, Gauge read full. Set the pot to 73 ohms. Gauge went to Empty. According to the Ford manual, my sending unit and gauge are perfectly within spec and should work. HOWEVER, When I set the resistance to 25 ohms, figured its around 3/4 tank, the needle stayed in line with empty. So I don't know what do do or check any more. I checked the entire system, with multiple grounds. Got 5 volts from my sender lead to just about every metal piece on the car. It appears the gauge doesn't want to work anywhere in between full and empty. The car sat for about 6 months. Gauge and old sender worked before. I also want to make note that when the ignition is turned on, the needle does move from below empty, up to empty, and results are the same in ACC position as well. All of my other gauges work great. My CVR is a solid state one from CJ pony parts and was putting out 5 volts which is what the Ford Spec is. I did check voltage through and after the sender and with the added resistance, it went down to 4 volts. Is 4 volts enough to move the needle? Tomorrow, I will see if I can check voltages at my water temp sender with the engine running, and see at what voltage makes the needle start to move.