04 cayenne S CEL code p0440 help

[MrFlip]

Hey guys! I've got an '04 Cayenne S and I've had it for a few months now. Shorty after I bought it I had the p0440 code, working at autozone and seeing this countless times I automatically went for the gas cap, seeing a cracked fuel cap oring I ordered one and replaced it. After replacing it I cleared the code and after a few days it turned back on. Next up, purge valve. Ordered, replaced, and cleared the code. Again after a few days it's back on. Now I'm kinda stumped, does anyone know what else it may be or if anyone has had a similar problem and what it was the fixed it?
As a side note, I have been smelling raw gas every so often and I had thought it was coming from under the hood but turned out to be from the tank area. My next idea would be evap hoses.
Any help would be greatly appreciated!
Thank you,
MrFlip

[MysticLlama]

The evaporator bellows can leak and cause that. Not sure if they can be replaced separately or if you need to replace the whole thing. It's in the passenger rear wheel well.

[MrFlip]

Is it called something specific or just evap bellows? Thanks for the quick response!