re: GMC Yukon - Fuel Pump Shuts off Constantly While Filling Tank (SOLVED: update pg 2)

If it’s like Doge and some others there is an anti-siphon mechanism right before the tank that’s spring loaded and will act like a check valve not allowing gas to flow if it fails. Try pouring some Marvel Mystery Oil to lube it up (won’t affect tank) and take a fish tape and try depressing the spring to loosen. The only way to replace in most cases is dropping the tank unfortunately but sometimes the Mystery Oil and fishtape trick will loosen the valve and get it working properly again.
I think the ethanol causes it to stick over time.