ford transit 125t350 52 plate do not rev up fine on tick over but starts to misfire at

[Jeffrey J]

2000 revs smokes as wel? when revs up could it be valve clearances

 

[mactheboat]

Is the smoke black? - start at the easy end - check the air filter.

 

[William E]

Valve seals, head gasket or rings!
Get pressure test.

 

[ivortskivor]

are you getting a management light displayed on dash? egr valve can cause a simmilar problem