2001 olds Bravada gas tank will not fill

My 2001 Olds Bravada 4.3 liter has 119000 miles the smog pump has been replaced with the mod and it still gives a code for the air pump. The fuel pump was replaced about 10,000 miles ago. Just reciently when you try putting gas in the tank the pump shuts off, the pipe is not dented or kinked the gas does seem to push air from the vent tube at the fill tube top. But the fill tube fill up before the tank is full. Any help would be appreciated. I am a construction equipment tech not an automotive tech. I dont have the money to keep taking it to the shop.