2006 Town Car. The fuel gage is never accurate, it wanders all over. Took it to a respected local ASE shop and after testing the instrument panel determined it was the float/sending unit which of course is built into the fuel pump. They replaced the fuel pump and it didn't fix the issue. They replaced the fuel pump THREE TIMES saying they were getting defective parts but It's still not working. Can ANYONE help me? $800 down the toilet for nothing.
Are they using OEM replacement pump assemblies or cheap Chinese parts? The level readers themselves are very simple things and shouldn't be bad that many times on Motorcraft parts. The float lifts up and down on a potentiometer, the same kind of electrical device that a dimmer switch in a house uses. Instead of the "dimmer switch" making the light bright or dim with variable voltage, the gauge is reading the variable voltage as a fuel level. If that's bad, it will read funky. A bad gauge could do that as well.
Also keep in mind the level will move a bit as you go up and down on hills. This is normal in older vehicles. My Ford Ranger's 7 years older than your Lincoln and the fuel level varies as I drive in hilly areas. The original sending unit has 263k on it, and it works fine.
Yes, all three have been OEM. But the gauge is not slightly off, it's WAY off. Sometimes reading half a tank after only 40 miles or reading empty after only 160 miles.
You need to trace down a problem in the circuit itself and I would suspect poor or corroded grounding connections.
