"Engine Malfunction- Reduced Power" seems to be BMW's equivalent of MS's
"Blue screen of Death" .
I'm @ 30,000km now &
It's happened on my x6 3.5i once, between X'mas & nyr's, but restarted engine & drove fine (thought nothing more of it over the holidays) until today,
i.e. Engine suddenly ran rough & Cntl Message threw up EM-ReP, tried restarting & ran ok for less than 1km. three separate times.
Called for app't to have dealer do their song & dance tomorrow.