hi all, Ive got a 2005 407sw 2 litre diesel X-line (no dpf) and driving home the other day i noticed that everytime i accelerated and put the car under load it was throwing out a cloud of black? smoke. The bottom of the bumper is covered in black soot. It doesnt seem to be using overly much oil, I am not getting any warning lights on the dash,also there seems to be a very slight hesitation before I change gear. The car has covered 130000 miles.It idles perfectly ok, doesnt stall and Ive checked the air filter and its fairly new and clean. Any kind person out there with ideas?