You're in good company Bimmer 4125. My 2006 4.4i has also started getting occasional SES-light misfires, shortly after I passed 80,000 miles. This can be caused by any of a number of issues: oil separator valve, spark plugs, vacuum leak, and/or an intermediate levers issue that was part of a BMW NA Service Bulletin. In my case the $tealer said my oil separator was fine and the intermiediate-levers did not apply to my VIN#. Anyway, they swapped out the spark plugs and the problem went away for a brief time. But I am still getting a mis-fire on about 1 in 25 starts. The common denominator on the Forum seems to be the COLD weather. I really think BMW does not have a firm handle on these E53 V8 cold engine mis-fires. It's one of those issues where they take stabs in the dark, which sometimes works, sometimes doesn't.

The way I am currently dealing:I wind up turning off the ignition, giving it a good 30 seconds to reset, and then turning it back on again. It has not been mis-firing on the 2nd go round. For now....