My Z did the same thing when i pull up to put gas , my gas was on E. first time filling it up since i brought it. i notice that. but it never did that in feb winter. now iam in summer in new york bronx. and it did it. i notice someone said on a hot day so i dont know it mines only did it when it hot , i never check it again after fulling up full tank of gas but i will check it again. its strange. heavy pressure of air rush out like u open a soda bottle. why ?