Help: 4000S fuel injection troubles

[eds%f9-a@Paoli.ATM.LMCO.COM]

I'm having trouble with fuel delivery on my '84 4000S.  This problem has
been intermittent for a couple of years, usually in the springtime, but right
now it's come to a head.

Symptom: the engine won't fire up.  Pulling the plugs shows them to be dry.
I could sometimes get it started by relieving the pressure at the fuel
distributor (opening a couple of lines) or by tapping the fuel distributor
while my wife cranks the engine.  Today nothing works.

I pulled an injector and verified I had no fuel spray while cranking.
I verified pressure at the fuel distributor by cracking the cold start line.
Then I removed the fuel distributor and checked the plunger.  I don't have a
tool to remove the stop screw so I couldn't remove the plunger for a cleaning,
but the plunger seemed to move smoothly, no sticking.  I reinstalled it and
checked the zero and basic settings of the air flow plate, they look OK.
The plate isn't sticking and there's clearance all around the plate.

Other FYI: both my grounds are connected at the intake manifold.  My fuel
pump is 6 months old.  I don't have any fuel pressure measuring equipment,
this is seat-of-the-pants FI troubleshooting.

So, does anyone have any suggestions before I go out and spend a wad on a
new fuel distributor?  Can a bad pressure actuator drop the output pressure
below the injector opening pressure?

Thanks,
Ed Skladany