Juddering on idle when up to temperature

[Frosty90]

I have 2005 transit connect 90ps tdci which was running fine until it started to go into limp mode and cut out with the glow plug light flashing, this was also combined with the engine running rough and also lots of smoke. I had the injectors tested and it came back that all 4 were shot, so I replaced the 4 and had them coded, the van then ran lovely for approximately 500 miles. Now it has developed a similar juddering to before but this only happens when the van is up to temperature and idling.

Has anybody got any ideas?