Put wynes dpf cleaner in tank and blast it on motorway in 4th gear for about 20-30 mins, only will clear if not that blocked, otherwise have to get it unblocked professionally at a cost of 400, I had 2006 is220d se-l got blocked on m25. It's all due to local miles. Had mine done from car surgeon in Birmingham picked up @ dropped off 400ish. But if u take to them they will charge around 200-250.only reason sold mine as didn't do enough miles. Try cleaning egr it will help, it's quite easy via utube, I cleaned my egr by watching utube.good luck