Apparently volkswagen didn't take off the cap at some point. As there is a tsb about if a customer complains about not showing full tank after filling up, the Pull the cap. There was no other hoses around or on the tank. No other places to even allow it to vent back into the tank like the lower vent tube. I no long have any kind of hissing when intake the cap off. Tank seems to be holding its Newely reformed shape (what a pain that was, to get it back to semi normal). Going to drive it a few more days then its getting parked till it goes to the dealer on the 23rd. Egr issues and also having them Look over the dsg as my mechanic says its leaking, when it shouldn't be.