On an oldsmobile 88 (l27) forum someone had the EXACT same issue and it WAS the fpr.

Re: "I probed the wire terminals of the fuel injectors, while plugged into the injector, with a test light and found that both terminals showed voltage. Should I be getting voltage at both wires on the fuel injector with the key in the on position?"

Each injector has a pink wire and, of course, another wire. The pink wire should have a constant +12V, the 'other' wire should show 0V with the key on. With the engine cranking/running the PCM switchs the 'other' wire to ground in order to fire an injector. If you probe the pink wire from any injector, with the key on, and connect the other test light wire to ground, it should burn steady. All 6 pink wires are common, so if one burns, they should all be OK, barring an open circuit near or on the engine. Its my guess that the reason you show voltage on both wires is you may have checked the voltage with the test lamp hooked up, which, in effect, makes both wires common.
The simplest test of all is to simply crank the engine with a test lamp hooked up. If it blinks during cranking, the injectors are probably working OK. Of course, to be absolutly positive you would have to perform the check on all 6.
As far as replacing the FPR, I doubt if that is going to solve your problem since you indicated that you have good pressure during cranking.

Fuel filter relatively new?

Not gonna rule out a pump, but when you don't bypass anything and turn the key on, do you hear the fuel pump cycle up[??? Pumps can go bad by just sitting unused. Seen it before. If that all checks out then try a regulator, i'm FINALLY buying mine tommorow.

I'm thinkin' Mos95b and Ranger are on the right track. The first thing I'd look at is the fuel pump relay, because it should energize the pump when the key is turned to the "on" position for a couple of seconds. If that doesn't happen, the relay or the relay circuit may be the problem. Plus, you can check it pretty easily and it'* cheaper than the FPR or the pump.

Oh, the fuel pump relay is located behind the passenger'* side kick panel in a relay center. Its location should be marked on the cover. If you jump terminals 1 and 4 and the pump runs for 2 seconds when the key is turned on, but not when the relay is plugged in, a bad relay is indicated.

me still thinks FPR... for a few reasons.
1. pressure drops after cranking <- doesn't get too much more clear than that
2. pressure builds when primed <- how will the fuel pump prime if it'* not working?

when you hook up a pressure gage, and you find that your pressure is not staying constant, I'd first look at the... pressure regulator...

I checked the pump, and fuel pressure regulator. Everything is good with these, but I found that my injectors aren't spraying fuel at all . In the process of checking the fuel pump relay I found the cars main CPU with the 3 plugs and another smaller aluminum box with only one plug on it, that is velcro'd in next too the main cpu. What brought my attention to the smaller box is that I noticed a "low" buzzing or hissing noise coming from it when the key is in the "on" position. Is this what controls the multi port fuel injection, and maybe my problem ? Anyone know what this smaller box is called? It has a "service number" of 1228874, as well as 2 other numbers starting and ending with "*" , and another number of 16081221 on the bar coded tags.

I did a little research and found the smaller box is the chassis brain box for the air bags and not related. Still wondering why my injectors won't spray?

I really appreciate all of your help with my car. I have used other forums before and I am just amazed at how many replies I have gotten. I think I found my problem and if it proves me correct or incorrect, I'll let you know the outcome. I was putting the air bag controller back in and couldn't help but notice a strong "burnt electrical" smell . So I disconnected the main cpu and took off the screws to the access cover, which was pretty beat up from the previous owner, and found that some large flat round thing (sorry, not too familiar with electronics) had exploded inside on the main circuit board. As soon as I track one down I will let you know the outcome.