1994 Honda Civic Fuel gauge

There is a sending unit in the fuel tank which could also be the cause. Remove the rear seats to get to the service hole and check the wiring. Color of wire from gauge to sending unit should be yellow/green. Earth it with ignition on and see if gauge works, if yes, the sending unit is the fault. If you need to replace the gauge, then you need to remove the meter assy which is not very difficult.