lvlark

Yesterday my focus (mk2 1.8tdci) just wouldnt start. had to turn it over about 15 times before it finally did. and when it did it ran as normal with no problems. then i left the car for an hour went back out to it and it started first time. then this morning i tried again and it fired up on the 3rd turn of the key but when i went to pull away it stalled and wouldnt start for another 4-5 times. when i did get it started it ran fine with no problems.
does anyone have any idea as to what the problem can be?
Thanks.