X5 4.8is rumbling engine noise on cold start

[-chc-]

Hi guys,

I've paid about 6000€ or 8000USD for a repair proposed by my dealer that didn't solve my problem. Have you experienced the following?

When it's cold (about 5C or 41F and below) I start my engine and it somewhat rev's up normally.

However, when I put in a gear (D or R), the engine starts rumbling heavily(!) and the whole car starts shaking. When I go out of gear (N or P), it takes 2-3 seconds for the engine to resume normal state operations.

BTW: the engine stops rumbling, when I gently push the accelerator or after about 20 seconds as the RPM drops. The engine light goes on, if it's really, really cold (below -12C or 10F). The rumbling only happens, on a completely cold start (eg overnight) and when the car is in gear.

My dealer has made significant repairs without success: they exchanged the eccentric shaft, cam shafts, intermediate levers, valves, updated the motor control unit, checked the valvetronic sensors, cleaned the gasoline input lines... all without success.

The car is a dream-come-true: full-option 2004 X5 4.8is individual with 90000km or 55000miles. I've just had the car for about 6 months, so I don't know the history to it.

Any suggestions are appreciated!
Thanks and cheers, Claus-Henning