Focus TDCI 2007 very odd problem

[TDCImark]

Hey guys, new here but long time ford owner (first time on a forum apart from capri owners club)

My 2006 focus 2.0 TDCI is being really weird lately. When started from cold, you need to keep revs up otherwise cuts out and dies, when revs are kept up, you get a missfire (especially around 1500rpm) with a moderate amount of unburnt smoke/fuel for around a minute,but the car drives fine, can pull off right away and it will drive fine, albeit the engine shakes when stationary. when the car has been started its fine for the rest of the day, but the slight shake is still there at idle. I dont get any smoke under hard acceleration, revs freely and no missfires.

I did notice this morning (uphill in 3rd) i can hear the turbo more than usual, would a split intercooler pipe cause this problem?

Code reader is not throwing a code, visual checks are done and nothing obvious is at fault. Ive ordered some new glow plugs as they are due, and while im there ill strip and clean the EGR...Is this a known problem and its getting frustrating on these cold morning (my area usually see's around -7 this time of year)