smoking diesel fiesta

i own a 2003 tdci fiesta with 115,000 on the clock ...it runs well normally but after 2 or 3 mins at idle ...when i accelerate again it leaves a cloud of white fumes behind ....it has new air filter ,fuel filter ,oil filter and new oil but the problem is still recurring...It sometimes stops smoking for a few days but the smell of fuel is apparrent after idling