Deisel Stutter - in between power and coasting in top gear.

Hi all - figure I will throw this one out there for people that know all about deisels.

Specifically it is a Ford Transit van 2005 2.4TDCi (turbo common rail) that I use for general travel. I have had no luck on any motor forums. The symptom while not a problem is annoying and I would really like to know what it might be ... as in ECU, dirty injectors, whatever - if an easy fix it would be nice - but it seems most "suggested fixes" involve lots of money.

When in cruise (usually 6th gear) and with your foot pretty much steady on the accelerator, when I am just at that tipping point where the engine transitions from very slight power to very slight coast or vice versa (possibly at the point the engine and diff are "disconnected" due to the little bit of play in the gear trains and 0 power trasfer) the bloody thing stutters a couple of times in quick succession (less than a second) as in power off / power on before it runs smooth again either coasting or driving. Speed at the time does not seem to matter be it 60 or 100 ...

I can get it on flat road, or in the bottom of a small valley where power changes from coast to drive are not large.

It never happens under load conditions either coasting or driving, only if you hold your foot steady and reach that "in between" mode.

The only other thing I will add is that it does tend to smoke a bit say if you sit at the lights for a while, when taking off (generally 1st and 2nd) it can blow a bit of smoke in the headlights of the car behind (only really noticeable by me at night more than day) but generally not continue once you accelerate past these gears unless you are really heavy on the throttle. No idea if this is related.

Ken