Cold Start Misfire

Hi Guys
My 1.7d Model B has developed a fault in that when first started will sometimes develop a hunting type misfire and won't rev much above around 3500 RMP (Getting there slowly) followed by the Gimp light coming on if I force it past, if I allow her to tick over and warm up a bit the problem appears goes away but there have been a few clouds of grey smoke which I take to be unburnt misfired fuel ? then she pulls like the usual Ox.....
Any help/advise would be gratefully received.

Cheers

Dean

 

New development today, set off for work with no issues until about 10 minutes into my motorway journey when it started misfiring and loosing power at 70 in the fast lane with no hard shoulder, finally managed to nurse it onto the bit where there was a hard shoulder switched it off and back on and it ran great for the rest of the journey? To say I'm confused dot com is a bloody understatement............