I plan to get my fuel filter changed soon as I have a similar problem. The engine turns over 4 or 5 times after sitting over night (didn't do this until it started getting colder out) but if it's been driven within a few hours it only takes 2 or so. Occasionally it takes longer than that even if the engine's still warm and it seems as if it might stall for a split second. I'm just hoping it's the filter.