Alright but I see no codes in the check control area or anything. No check engine light. But if there are codes that can be triggered in a hidden fashion with no indication, and can only be read by a tool, then that seems pretty stupid. But just my rant.
Anyway, I did more testing and it doesn't seem to happen when a/c is off. When I switched a/c off another oddity occurred in that there is a DEEP low frequency RUMBLE that almost hurts my ears when the ac is off and I am in D or R. This goes away when the a/c is on. So bizarre.
Also I noticed when the problem happens, the car just wants to lunge forward. It almost seems like it is not caused by the engine at all but maybe transmission.
I'm a bit new to BMW and so far not impressed mechanical wise though the interior and exterior design quality in this car is world class. I've been in a few Benzes where i can neither hear the engine, nor rumbles nor vibrations. They're smooth as butter.