During your troubleshooting, if you happen to zero-in on the fuel lever sensor, here is something I ran into.
Here are pictures of a new tank lever sensor compared to one that is less than 10 years old. As you can see, the parts that were not coated already have corrosion and rust. Why? Old Ethanol (E10) gasoline. The sensor itself is basically a variable resistor that makes physical sliding contact corresponding to the level of the gasoline in the tank. The sensor could have rust or corrosion which could cause the fuel level gauge to read incorrectly.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
