Honda Repair: fuel guage, fuel guage, empty tank

Question
when I fuel up the car the guage reads full for a while then it drops below empty then rises to a half a tank. Could it be the ground or sending unit itself and can I check it buy pulling out the back seat through a plate in the floor its a 91 accord lx  

Answer
Albert:
My guess is the sending unit. You are correct in the location, behind back seat through an access cover. You will need to check with an ohmmeter for resistance on the electrical connectors. Check with the float in the bottom (empty tank) position and you should have 105 to 110 ohms. Next check the half position and you should get 25.5 to 39.5 ohms, then the full position and there should be 2 to 5 ohms. If you are not receiving these readings then replace sending unit.
Good luck.
Bill