Larry,
I suggest replacing the fuel pressure regulator. (WOW I just looked up the price of those things!!! When I replaced my fpr it did not seem to cost that much.)

Anyway, before you replace the fpr do a fuel line pressure check. This will give you an idea whether or not the fuel pumps are building enough pressure to the fuel rail. If the fuel injector rail is not holding pressure it is possible because the fpr is not working properly. In addition, if you fuel injector rail is not holding pressure then it is possible to have a leaking fuel injector.

If you decide to replace the fpr be careful not to blast yourself in the face with fuel from the injector rail that has pressure built up in the line. I recall that the fpr has a ring holding it down sealed into the fuel injectors rail. In some cases it may pop out or it maybe stuck into the rail after removing the ring clip.

By the way, when was the last time you replace your fuel filter?