Having trouble filling gas tank . No codes and noticed when I took off filler tube this is on the tank . I dont know what it is or does . I can touch it with my finger and it kind moves . Anyone know what it is for and purpose ?

 

This photo is the inlet on the fuel tank of a 08 avalanche ,Anyone any idea if this is needed and purpose . I am thinking of breaking this off if I can .

 

Supposed to be there. You likely flooded your evaporative emissions canister and vent valve. Do not keep topping off, after the pump stops it’s done, don’t keep filling