Why does gas back up when filling tank and pump keeps cutting off. on 2004 Lincoln Town Car

can't fill up gas tank, gas backs up and pump cuts off

Asked by for the 2004 Lincoln Town Car
It could be the vent line is broken/bent or not connected or clogged. If you remove the fuel tank and replace the filler neck (it should come with a vent line) you will be good to go. I would also check the tank for any issues such as rust or dirt that can clog things.