Bringing this back from the dead with hopes someone ultimately got to the bottom of this. Happened to me tonight slowing down from spirited driving. That's twice in one month. Bone stock (well, added Pedal Commander yesterday). Thankfully I have the 6 SP, so it starts right up as I'm rolling in neutral. Seems to be the same each time happens when coming down from spirited driving. All of a sudden the start button starts flashing and a message pops up between the gauges saying something like, "accessories...only", couldn't ignore cars around me to read it.
i had a similar problem with my mazda 626. Random engine shutoffs. Very scary. Mazda pursued it and found that it was a capacitor that was bad in the electronic distributor. Just a data point.