Before anything else when the van refuses to start, can you get spark?  Do
you hear the fuel pump run?

Check by removing yours and putting in a known good one the following
1. The ignition module,  little black thing mounted to heatsink on the wall
of the van, had one fail by starting like you describe and then one day
nothing, no spark, dead.
2. Main relays in the little black box in the engine compartment, can kill
electricity to the fuel pump or the computer
3. ECU, borrow a good one, don't buy one until you know yours is bad!  Bad
ECU does all sorts of strangeness

Hope that helps,
Dave K.