I have a 2008 Hyundai Sonata that overflows at most gas stations when filling. To fill the tank, I set the pump on autofill and walk away. The pump clicks off and then the car "burps" and gas comes out the filler neck and runs down the outside of the car and out the bottom. It does not do this at one gas station by my house but seems to at all others almost every time. The car is still under warranty (42,000 miles but the issue started at 29,000) and I have brought it to the dealer 3 times. Each time they claim to have found something new wrong and fix. The first time they replaced the fuel filler neck, 2nd time fuel filler neck assembly (and tested at a gas station and it worked), 3rd time the vent valve. Each time I try it and it overflows for me (except at that one gas station). I have never had this issue before with any other car including my wife's current car.
I'm truly stumped, but feel that a car should be able to fill up at a gas pump without overflowing.