Having a wierd problem with 2000 passport.  When I turn the key to
start, the following happens:

[A] the fuel pump relay "buzzes" for about a second

[B] about a second after that, a device on the fuel rail starts making
a rapid clicking sound that goes on for about 2 seconds.  While this
is happening, the internal check engine light seems to be flickering
rapidly on/off in sync with the clicking.  If you are standing in
front of the truck, facing the radiator, the clicking is coming from
some sort of sensor or device that is at the back right corner of the
fuel rail (close to the firewall).  It is some sort of cyclinder that
has a wiring block with 2 wires on one side, and what appears to be
fuel in/outs on the other.

[C] During this whole process, the fuel pump sounds very sick.  It's
running, but it sounds like crap.

[D] after the above, the engire doesn't turn over.  It doesn't do
anything.  If I restart the engine start sequence, the same behavior
happens.

Some things I've tried that didn't change the behavior:
I've tried moving another relay of the same model into the fuel relay
position
I've cleaned the posts of that relay (and all the others)
I've left the vehicle without any power (unplugged the battery) for
hours
Cursing. Lots of cursing.

Now at this point, it sounds like a bad fuel pump, but these 2000
Passports have tricked me in the past.  Has anyone else had experience
with this, and if so - is this a fuel pump issue, or is their an
uphill electric/sensor issue here (like whatever is making that
clicking noise (see [b], or some sort of fuel cutoff switch gone bad)?

If it is a fuel pump issue - how hard is it to change to the fuel
pumps for this model vehicle?