If you can start it with starting fluid, then is is gas related.

Did you disconnect the fuel pressure regulator and test the PSI and see if it rises to the spec I posted above.

Another possibility is the individual fuel injectors are not being told to fire, or at the wrong time, or fuel rails are clogged. I would think there would be a code for this, but do not know.
The computer could be bad too for all I know, and not telling the injectors to fire. Maybe wiggle the connectors to the PCM

I am not familiar with MPFI systems, so Alloro and MAR have to jump in and take over, cause my ideas are exhausted.

Before pushing it over a cliff, let me know, I could salvage some parts........

 

I believe your gas tank is full of crud and clogging up the filter after it runs a bit. Pull your filter again and check it out, probably full of stuff. Did the van sit around for quite a while before you bought it? Tracka96