Well, we're all trying to help. What will help us help you is to know (with the 3/4 tank of gas you have) what the resistance being fed to your gauge is. You can tell us that by disconnecting both wires, setting a handheld multimeter to resistance (there may be a low setting and a high setting or it may decide automatically for you), touching one of those leads to the center post on the sender and the other to ground.