I Have the same soot problem. I have replaced the large intercooler pipe at the front and the pipe at the rear with the sensor in it to no avail. Loads of smoke on mid to heavy acceleration, then the engine requiring service sometimes comes on and the engine seems to go into safe mode and won't go above 60 mph por a short time or until you switch off the engine and restart. Any help this is driving me mad (pardon the pun if it is one!!)