One problem related to engine shut off without warning has been reported for the 2008 BMW 328. The most recently reported issues are listed below.
My wife was driving home from work on the highway at night and her entire car just shut off without warning nearly causing her to be killed by a tractor trailer we had car towed to BMW dealership and they say valvetronic sensor/seal issue. . . But this was scary and nearly killed my wife so I felt compelled to report this issue.