If there is spark, you can rule out the ignition problem. Cold start problems usually has something to do with the air intake system. My 1994 850 had some problem starting in the cold morning about two weeks ago. I unhooked the Idle Air Control Valve and cleaned it thoroughly with some carb cleaner, let it air dry and reinstall it after 30 minutes. I have not had any cold starting problem since. While you are at it, might as well clean the throttle body.

The Air Mass Meter or the Mass Air Filter could be at fault, which is a common problem for many stallings while the car is in motion, at high or low speed.

Another place to check is the fuel pump relay. In any event, it costs around $50 and if your car is already aging, I would buy a new fuel pump relay as a spare for a sudden death situation or as a fix for the non-starting/stalling episode.