Do you have a steel gas tank and is it rusty? If so, it may have lost its ground for the fuel pump. Use a test light to check for voltage between the tank and the body or frame while a helper turns on the ignition switch. If you see voltage on the tank, drill a small hole on the flange well outside the weld, and use a screw there to attach a ground wire. Run that wire to a good clean spot on the frame or body.