that plastic cup looking thing with a thin rubber gasket inside, that the fuel cap presses against...i have a slight gap at the bottom, i thought at first it was the fuel cap, so i replaced, but still have that gap and still have a vapor leak...was wondering if that might have something to do with the vapor leak code p0455?

 

I don't think that code is related...I broke the clips of the top of my pocket, which caused the fuel door to not sit completely flush, and it didn't cause any codes for me