Mystery issues…this van runs great most of the time then shuts off w/o warning, it will shutter like the front end is going to fall out then shut off or not? We’ve been to 3 mechanics and 2 said “Thanks for the bus. but don’t bring it back” Any ideas other that explosives?
When it shuts off, will it restart right away? Do warning lights come on?
It may be fuel or spark. Likely compression is OK.
If it does not start right back up, let’s check for spark. Buy a spare spark plug. Next time it does it, remove a spark plug wire from the plug and put it on the spare. Hold the threads of the spare tight against the engine and then have someone crank the engine while you look to see if you are getting a good spark.
If you get a really good shock, then that means you did not use a very well insulated tool to hold the plug while your friend was cranking the engine. 
If it does not spark, it is likely an ignition system issue if it does then it is likely a fuel issue.
If you don’t remember when it last had new plugs & wires oil, fuel and air filters, then now would be a good time, one of those might catch it.
What does the exhaust smell like? Does it ever smell like gasoline? Does it smoke?
IF, in fact it does stutter and stumble when it quits:
I would change the fuel filter first (it’s easiest to get to).
It’s located in front of the fuel tank attached to the frame rail, passenger side.
Relieve the fuel pressure first by removing the fuel tank cap and relieve the fuel pressure at the fuel rail Schrader valve.
What Joseph asked at the start of his post: will it restart right away?
If it doesn’t, you MAY have a fuel pressure regulator fault.