Looking in my 93 manual, the sending unit is 0 ohms resistance at Empty.
It is 90 ohms on Full. So the higher the resistance, the higher the reading on the gauge.

So, an open in the circuit would probably give you a constant Full reading.
When you drop the tank, you should be able to short across the 2 sending unit wires and this should give you E with power on.
If it doesn't, it is likely something other than the sending unit. A bad connection at a connector or no ground to the sending unit.

You should be able to ohm out both wires at the sending unit (disconnected) and one side should be a dead short to ground. On mine it is the black and white wire.
The black wire goes to the gauge at the dash.

With the results of that step, some of us could probably guide you to the cause.

Bill