Is it possible that the dual-mass flywheel of my 535i M 1989 (272000 km) be the cause of intermittent engine vibration (engine running rough, feel the vibration on the steering) when running on the road what ever the speed is (run mostly in the 115-120km range) ?

It may run smoothly for one ride and vibrate during the next one.

My Dual-mass flywheel generate like others that well known nucking noise / diesel like when the engine is running idle and when the engine is switch off; but could it also be overtime the cause of the kind of describe vibrations ?

Engine supports was check OK, visualy the guibo look fine too, tires new and well balanced, right trust-arm bushing just start giving some vibrations when braking (not all the time)... but it's not supposed to cause constant vibration like the one that concern me.

Your tough please. Claude