[12Ounce]

You are making me recall a fuel gauge problem that I once had on a mid-80's Escort. It was very unreliable. A co-worker suggested replacing a "voltage regulator" that resided on the printed circuit "board" of the instrument cluster. I had never heard of such, but after getting one from the dealer and installing all was well. I think the thing was call an "IVR". Instrument Voltage Regulator????

Don't know if that could be your problem or not.