Sounds like a fuel problem. You want to start small and work up. I would change the fuel filter first, then the ingectors, then the fuel pump. I would also put some of that 44k fuel system cleaner in. It comes in a small black can and works real well. As far as the gas I dont know. You should find a gas station that has real good gas and ALWAYS us the same kind (just that company) I use Total gas. ALWAYS us as high of octain as poss.

But I would try a full tuneup before I started replacing things like the fuel pump. Clean air filter, new oil filter and change, new fuel filter, and clean the ingectors, etc.

Hope this helps give you some ideas. When you find out what it is post a rep. I would like to know what it ends up being.