Fuel Pressure Regulator? Fwd: sudden stops

[D Daniel]

Thanks for help from those who responded off line.
Replaced the ignition wire set so now have plugs, wires, rotor, cap, 
coil replaced.
This is the NF engine with the CIS system.
Did find a vacuum line to the fuel pressure regulator which had a 
dubious connection (split end and not fully seated).
Bentley seems not to fully define the function of this component.  {The 
reference page to FPR test procedures seems to be in missing}
Any thoughts about this being the source of my problem?
Seems like a very possible suspect but would appreciate some BTDT 
confirmations.
Thanks again,
don

P.S. The odd part of the symptom is that the engine stumbles when it 
dies (i.e. does not quit instantly)  but will never recover without a 
restart.  Restarts easily as if nothing was ever wrong.  The fact that 
it dies gradually rather than all at once leads me to fuel rather than 
ignition.

Begin forwarded message:

> From: D Daniel <d2.daniel at comcast.net>
> Date: December 14, 2004 6:03:36 PM PST
> To: quattro at audifans.com
> Subject: sudden stops
>
> My 91 100Q  (110K miles) has developed an annoying problem.  The 
> engine will quit suddenly without warning!  After a great trip to 
> Monterey it quit about 30 miles from our house during a 100 mile trip 
> home after running flawlessly previously.  It then continued to die 
> periodically during the last 30 miles.  Always would re start quickly 
> but this happened 6 or 8 times towards the end of the trip.
> New plugs, new rotor & cap.  New coil & fuel filter.  Had previously 
> behaved this way and was hoping the fuel filter and/or coil would fix 
> it.
> Runs great. Passed smog no problems 6 months back.  Fuel pump?
> Any thoughts appreciated.  Thanks, Don
>