Excessive soot and carbon build up in the intake manifold and intake valves of the 335d which is a diesel car. this causes rough idling, misfires, and loss of engine power. while merging onto a highway, the engine malfunctioned due to this problem and immediately lost power almost causing a collision. the vehicle has had this problem for more than 20k miles and continuous trips to the dealer to diagnose. finally, the dealer agreed it was carbon build up but that it is not covered. the repairs for this should be covered by bmw as it is emissions related and can cause significant engine problems. this has not been an issue on other diesel cars by other manufacturers. *tr
Due to premature build up of excessive soot and carbon in the egr, intake manifold, and intake valves of diesel engines, it was cause engine vibrations and check engine light to illuminate. without costly repairs requiring egr cleaning/replacing, intake manifold cleaning/replacing, and cylinder head cleaning/ replacing, the car will not pass mandatory emissions testing. bmw needs to extend their warranty to address this issue.