Bad Fuel Pressure Regulator?

I've got a '87 na 944 that shuts down on me after driving a few miles
(under 10), and I'm unable to restart.

It's happened to me 3 times, and the 1st 2 times I had the car towed to a
mechanic that said the car was running fine.

The 3rd time was Wednesday after picking up the car from the mechanic and
driving about 1.5 miles. While trying to start it after the shutdown, I
was able to verify I WAS getting a spark. I installed a DME relay jumper
(http://clarks-garage.com/shop-manual/fuel-05.htm (http://clarks-garage.com/shop-manual/fuel-05.htm)) and it did NOT help the
car start which I'm rules out a bad DME relay (replaced in 2002).

I did find that after leaving the car shut down for 5-10 minutes, the car
would start and run for about 2 seconds before shutting down. I repeated
this several times. I unplugged one of the fuel injector plugs and the
car started and I was able to drive the car home (about 7 mi.)

In reading Clark Fletcher's troubleshooting guide
(http://clarks-garage.com/shop-manual/ts-01.htm#fire (http://clarks-garage.com/shop-manual/ts-01.htm#fire) (under engine
difficult to start when cold)), the problem seems to be high fuel pressure
due to bad fuel pressure regulator. The only thing that might not fit is
the fact I was able to drive the car 5 miles or so the first two times I
had the problem.

I'm wondering if a new fuel pressure regulator is a sure bet, or do I need
to verify high fuel pressure with a gage & adaptor (I don't have)?

What about the fuel filter? But I think you might be on to something with the fuel pressure regulator.