Low pressure on the fuel line could have also been caused by the Fuel Pressure Regulator being faulty, which is a common problem on VX's
I don't know exactly what goes wrong with the stock FPR's on VX's, but given the mileage on the one you purchased, it's likely that the original is still in place, so it would be a likely place to start.
Okay, sounds like a good thing to replace in any case. If the FPR is the problem anyone have ideas on the mechanisms whereby it'd cause the issues I'm seeing (how would refueling get the FPR working right for an hour)?

Congrats on the purchase, and welcome to the site.
Appreciate it.