I am having the same issue, please let me know if you find out

 

you need an inline test port adapter that plugs in the quick snap connector between the pump and filter or main fuel line (if your van does not have an external filter)..
the regulator is part of the pump assy and a pickup screen (sock) filter is on the inlet tube.
Some vans (seemingly the earlier 4th gen) had a fuel filter that was mounted atop the fuel tank, but some might have no secondary filter

 

so how do you get that connector off the fuel line at the engine. It's different that what I found at the fuel tank (2005 GC 3.8)

 

you don't need to pull the fuel rail connector for a fuel pressure test.. you need to find a quick connect fitting in which to install the pressure test adapter (Miller #6539 or similar aftermarket or Mller #8974 package can be used..)