Pelican Parts Forums - another gas smell question

I have searched the gas smell issue and noticed that most say replace the lines and the filler cap gasket and some even the sending unit gasket but i haven't heard anyone with this issue yet. so i get the gas smell in the trunk and abit inside the car at start up. after about half a minute its gone and will be gone for the remainder of the day even after work (9 hrs). i have replaced the gas cap gasket which seemed to work abit. am wondering if its the sending unit gasket or the lines in the trunk or the carcoal canister. if the canister, who sells replacements or is it i have to plurge it with something?
ken