Fuel Gauge Trouble Shooting Help Needed!!

I will check the connection behind the kick panel that should be ez, I didn't know that the temp gauge and the fuel gauge rely on the same regulator, I don't think that is working either, its been years since the car has been in service about 10 years ago the auto trans started slipping that lead into a 4-speed swap that lead into a floor replacement that lead into .......LOL, last I remember the fuel gauge was working but inacurate. well you guys gave me some great advise so I'll see if I can get to the bottom of this. Thanks