The fuel tank pressure valve may be leaking on top of the tank that's why you smell it and can't see it also could be the gasket for the pump do you remember if at one time driving off a high curb or hitting something high enough that you banged the tank against it could be also your pollution canister and evap canister purge solenoid valve or hoses could be leaking or the fuel tank filler pipe gasket or bypass line on it could be rusted out especially if this is an older vehicle like in the 90's you didn't specify year also did you get codes that said you have a misfire or are you just saying that the engine is running rough please post back and be specific about what your trying to tell us because obviously none of us are there with you so we can't just ask a question or check ourselves you must be specific here you are our eyes and ears from afar good luck stephen
Answers & Comments
The fuel tank pressure valve may be leaking on top of the tank that's why you smell it and can't see it also could be the gasket for the pump do you remember if at one time driving off a high curb or hitting something high enough that you banged the tank against it could be also your pollution canister and evap canister purge solenoid valve or hoses could be leaking or the fuel tank filler pipe gasket or bypass line on it could be rusted out especially if this is an older vehicle like in the 90's you didn't specify year also did you get codes that said you have a misfire or are you just saying that the engine is running rough please post back and be specific about what your trying to tell us because obviously none of us are there with you so we can't just ask a question or check ourselves you must be specific here you are our eyes and ears from afar good luck stephen