My purge system has failed again somehow, I have again a heavy fuel smell in the trunk and cabin but now when I pop open the fuel cap I can see gas pumping from the overflow down into the neck like a waterfall of fuel. Thoughts? As a side note my fuel pressure regulator is dying, but I don't suspect they are related

 

This may or may not be a reason ?? There is a rain water drain opening in the gasoline fill sump. Is it clogged? If so, this might be creating a vacuum. Causing the gasoline to rise up into the fill tube. Point being there is not sufficient air to keep the gasoline settled. Had this issue on my 93 XJS.