I'm having some problems with my 2004 Mondeo 2.0 TDCI (MK3). I found that whilst the engine is cold (say early mornings) if I get up to speed at sit at a steady 30 - 40 mph with steady revs the car will start to judder slightly. It feels like it wants to cut out but it doesn't and no lights come on the dash. If I accelerate or deaccelerate then the juddering goes away. It only appears when I sit with steady revs. I've found it happens most at around 40 mph with 1.5k - 2k revs.

Once the engine has warmed up the juddering completely disappears. I originally thought the EGR valve might need cleaning but I can't see why the juddering would disappear when the engine is warm.

There is no smoke out the back, and no dash warning lights on. I'm confused!