My E90 318i 2006 (N46b20 engine) has had this grumble for a while now, only occurs when the engine is cold and I am in drive at a standstill (in the video around the 13 second mark you hear it after I switch to drive).
The vibration disappears with the car warming up, almost like something disengages/uncouples after a couple of seconds at a standstill in drive (e.g. traffic light). There is no sound at all when I put my gear in neutral at standstill.


I do not have any related error codes in INPA (only codes there are for my auxiliary water pump, empty battery of external alarm, and IBS signal). In the past I have found my eccentric shaft sensor in that fault list, but that has not occurred anymore since I replaced my battery.

Anyone any idea on how to approach trouble shooting/repair?

Recent repairs/maintenance I have done:
-Let ZF flush my trans (they found some wear on my 4th gear, and minor slipping). Before flushing my trans the car would shudder and even at some point stalled when I braked hard on a cold engine (this could be prevented with moving the gear to neutral and than start braking)
-Cleaned my Vanos solenoids and replaced gaskets (previous owner really messed it up with liquid gasket)

Other observations:
-It seems my car has been doing less Km/L (now at ~11 km/L) mixed driving, and about 14 Km/L highway driving. Could be the cold though.
-Slightly bouncing idle (100 revs?), not sure if this is also the case with a warm engine.


Video with groan starting at 12/13s mark:
https://www.youtube.com/watch?v=HiUw...ature=youtu.be