1996 Ford E-Series Van engine dies silently while idling/wh

Engine Performance problem
1996 Ford E-Series Van V8 Automatic

I have a hightop custom 1996 ford econoline 1500 van. For the past 2 months it will just die on me. First it was just while idling at a light or drive through. Then it started to die while I was on the interstate. It gives no notice, then it takes about 15 minutes to get it to start back up.
I had the fuel pump replaced- it was bad, after this is when it started to die while on the interstate/while driving, not just idling.I've taken it to two mechanics they both kept it for over a week. They said that it checked out fine on the diagnostics, and had to drive it
and it stall on them to know what is wrong, thing is they said the van never stalled on them. Please I hope you can help.I'm at my wits end, I can't afford a new vehicle, been driving my sons to work, any leads as to what might be causing this?