I agree with CTSportX5 - it sounds like Intermediate Levers. Even in our (relatively) mild UK winters, this problem arises. My dealer replaced the ignition coils initially (as the codes indicated misfires) but this did not solve the problem. They eventually traced the fault to the Levers but tried to say they were "within tolerances". I fired off a letter to BMW's UK HQ saying that it was ridiculous that a £60k car (mine has a lot of extras) should misfire when it was very cold and that there was clearly a fault with the quality of the levers. They offered to pay for the parts but not labour - my dealer offered 10% off the labour charge. In the end, I managed to persuade my aftermarket warranty company to cover most of the labour charges. However, I have to say that I don't think the problem has been totally cured! I have read that it doesn't cause any harm to the engine but it surely must do as it must put extra stress on the crankshaft, etc. I'm afraid it's a very common problem with the V8s.
I have posted o n this several times before but as the V8 versions are not common over here, the usual apathy reigned and it wasn't really followed up.
Why don't you speak to the Swedish BMW HQ?