I like your fuel pressure regulator suspicion, or thinking about it.

did you test fuel pressure on the engine ............that port there in the
T fitting, to the right of the distributor ?
I would.
see if the fp regulator is controlling fuel pressure corretly ......both
with vacuum line connected to it, and disconnnected.

that's the only fuel pressure test I rely on- on the running engine. around
30 to 34 with vac line off -  it's close to that. Bentley knows.

I also run them off a can of gas if I suspect the fuel tank.
I like having a spare known-good fuel pump and fuel pressure regulator
around for testing purposes.

did you check fuel return line to tank ???!!!
if that was clogged, fuel pressure would get very very high. The 'dead end'
or 'no outlet' fuel pressure can go up to 100 psi.

also .....it's not unheard of for there to be a faulty brand new vanagon
fuel tank.
It's not from China is it ??
I;m joking, but not completely, not completely at all.

you could try this ............run it, with fuel from the tank, but don't
run the return back to the tank.
Run that to a can or bucket.......
for two reasons........one just to see that it's flowing in that line.
At idle the pump pumps probably 10 times what the engine takes off to run on
......so I would expect good return flow.
Secondly......to see what that fuel and whatever might be with it, looks
like.
Scott
www.turbovans.com

----- Original Message -----
From: "Steven Mills" <StevenM@RED-ROCK.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, July 28, 2009 2:23 PM
Subject: 90 Vanagon/Westy fuel problem

15 yrs at driving a Vanagon and do my own work, yet this has me stumped.
Recent loss of pwr while at highway speed. Acted as if it may be a fuel
filter and I replaced. Immediate improvement. Happened again a few weeks
later and left stranded on road side. Always have spares of pump and
filters, as I am often where they can't be found. When I took pump off,
inlet was clogged with sediment. Definite time for tank replacement and
did so. No luck. Would crank and fire, just no fuel. Looked under to see
that tank had sucked up in a concave manner, so took line off and blew
out with air hose to pop back in shape. Would then start, but run for a
few seconds and die. Tried with gas cap off, etc. took all fuel lines
loose and blew thru them. No fix. Bench checked fuel pump and it
pressures right up. Could the fuel pressure regulator valve been trashed
with the suction that caused the tank to collapse? Something is not
letting the system pressure equalize as the fuel level drops is all I
can think of. Any ideas?