ive thoroughly looked through past posts on fuel gauge issues, but im still stumped. when i disconnect the wire in the trunk from the sending unit's tan wire, the gauge reads past full. when i then ground that wire, the gauge reads empty. from what ive read, this means my gauge and its wiring are ok. the problem is, when i have the sending unit hooked up and i move the float to empty, the gauge reads empty, but when i move the float to full, the gauge only goes to 1/4 full. is my brand new sending unit bad, or what can be causing this?