plz help

[macamac]

hello all,,,my first time here,,,, i hav a 97 transit 80 break,,i tink its a 2.5 straight desil,,it will go wiv a toe,,but only drive for about 5 mins,then stop,but if i toe again it starts again,nd just do the same thing,,,, nd theres loads a black smoke ,,,, but it will sit an idle all day,can anyone plz help me in any way...tnx.

[AndyG]

Timing belt jumped a tooth
Fuel filter last changed