1996 Chevy Truck abrupt shutting down

Would like to know if you have any info. On the engine just shutting off. You will be driving along and it will just shut off, then you might sit there for a few minutes and it will start right up and run just fine. You will know if it is going to start or not because if the "wait to start" light comes on it will start(diesel). I had it to a dealer but they said unless the engine light was on that they wouldn't be able to find the problem without a lot of searching. The engine light only comes on if it doesn't start, but by the time I would get it towed to garage and wait til they could look at it the truck would start right up and the engine light would be off. It only seems to do this in the winter time. Any info. Would be greatly appreciated. Thanks Bud