[Gregte]

I believe that cars of yore used a wire wound rheostat inside the fuel tank as the variable resistor for supplying a signal to the fuel gage. This would give a rather coarse resolution but certainly work for the on-dash gage.

I am wondering if this is still what is used for the fuel gage 'sending unit' or if something with much better ability to finely resolve the level is used, such as a regular carbon pot.

Just wondering if it would be worth the trouble to tap into the fuel gage's signal wire and feed it to a voltmeter, which can resolve to hundredths of a volt, for the purpose of being able to know very accurately your fuel level, such as when parked on your level garage floor.