I had a BMW that used to do the same sometimes but only with cold engine in the morning. The engine had the valvetronic system (1.8 16v Valvetronic).
They told me in the dealer that sometimes that could happen until the valve system started working weel (after some seconds). Do you know if the new 6 cilinders engines (2.2;2.5;3.0) have the valvetronic system?

 

no...there is no valvetronic system. I think it is double vanos. Have you check wif your pals if they have the shaking feeling in the morning? You will be surprised to find that some don't have get this. It concludes that the shaking thing can be eliminate by tuning. Or probably some parts are faulty. I just don't know where is the fault. Even bmw dealer can't resolve it.

 

The valvetronic engine had the VANOS system too. Maybe the injection isn't working properly. A visit to the dealer and try to reprograme it.

 

is it? they seem to be unable to find the fault. If that is the case, i will ask them to reprogramme it.

 

Ask them to keep the car in the dealer for the night, then in the mornig you and them together start the car and check the engine failure.
That was the way that i solved my problem because the computer didn?t show any problem.
Don't give up on this matter. We are talking of a six in line engine.