My car sits for about a week at a time while i'm at college, but it still should do this. I'm driving along at about half throttle and get almost to 4k rpm and it just drops to 3k for a second, almost like I down shifted. Except i'm not doing anything. It just holds there for a sec then just keeps going like normal. It only does it every once in a while and seems to go away after I drive it for a while. Anyone have this problem or have any idea what it could be?