you know rotten eggs could be a clogged cat, do you remember if you did use different fuels, I would seriously recomend some complete fuel system cleaner, which i very possible changing fuel types and it will make your car run way piss poor and can cause a lot of problems if it is not remedied!!!!! If you can push down your shrader valve on the fuel system and get a huge spurt of gas your fuel delivery up tp tha point should be good. But really check he cat, run premium, add some booster, it has gotta be in one of those things!