Nozzle keeps shutting off when I try to fill my gas tank

Most likely you have a bad Vent Solenoid. If you over fill your gas tank, the gas will eventually go into the vent tube and your vent purge valve will fail. I have heard of some people actually filling the charcoal canister with gas. If your check engine light is on, you should get the codes read. Here is a link. You can see the illustration in the link. See how the vent tube leads to the vent solenoid? Just imagine over filling your tank to the very top of the filler neck. See how the gas can now leech back through the vent tube? That's what will cause your solenoid to fail. http://www.aa1car.com/library/evap_system.htm

Assuming your gas gauge works? The new systems are " closed" so as to not allow fumes to disperse into the environment! When you fill the car and the gas pump shuts off the pump DO NOT CONTINUE pumping gas to Top it Off as we did in the 70s ! The vent tube will fill with gas! The one easy check is to pull out the nozzle of the gas pump an inch or so but still in the main tube when filling your tank, some pumps are sensitive to the backdraft of fumes from the gas you are pumping and cause the pump to prematurely shut off! I have experienced this condition more than once! By venting the main gas tube your allowing the fumes to bypass the gas pump sensor at the nozzle! You will notice that the newer gas nozzles have a large circular disc around their nozzle that is there to sit flush against the gas tube similar to a gas cap! This is to prevent fumes from escaping when you are pumping gas into your tank! So never overfill the tank or as Reelin68 you could have serious issues! Hope this helps!