It sounds like fuel pressure drop off. Have you checked that? Also, and this isn't related to the gauge, but have you checked the coolant temp sensor to make sure it's telling the computer the right info? If it's saying it's extremely cold or hot, the fuel mixture could be off and preventing the engine from starting.
Once it starts with starting fluid, does it run normally after? And as far as the gauge, it could be an issue with the PCM. Have you checked for corrosion or damage to the pin in the connector? Take a look at the two pics. The first shows the level sensor in the tank. The ppl wire comes direct from the PCM. Have you checked it for power? The second pic is the other end of that wire at the PCM.
Also, confirm ground for the level sensor. It is part of a splice which may have failed. You can see it in picture 1.
Let me know.
Images (Click to enlarge)
Friday, August 9th, 2019 AT 8:00 PM