i have no idea what this is. i was driving through town 1 day with a friend, my car was warmed up for 15mins before driving, about an hour into the drive, my car starts "puttering". what i mean by that is, around 2.5k rpm it will sputter until i hit 3k. i explained it to a guy at my local advanced auto parts store and he couldnt place the problem, he assumes the fuel pump. does anyone have a clue?