I can't answer your question but I know exactly what you are talking about.
Several years ago, we took in a PERFECT 1995 Grand Caravan. It was a 4WD model with every option. I thought it might make a good "extra" car so I bought it.
I quickly learned why it had been traded in. It would do the exact same thing and it would do it at the worst possible time.
It was like shutting off the key. No power, no power steering. IT would dit for awhile and start right up. It might be fine for an entire day but usually not.
I had it at a top notch shop three or four times. They did an "update" on it, checked all of the grounds etc. They couldn't get it to act up.
It was actually dangerous to drive especially on the freeway. We took it to the auction and I took a bath on it.
So, I'll be curious to hear if you get any responses.
Oh, ours only had 65,000 miles.