fuel pressure questions

[bhawk]

94 ranger 4.0. Was running and got to about operating temp and then we shut if off. It wouldn't start up right after we turned it off. Cranked over fast but no fire. We pushed it into the shop and I tested for spark at the plugs. There is spark. So, I listened for the fuel pump. It clearly comes on when you turn on the key. It runs for say 5 seconds then turns off. I assume that is correct as it primes the system I presume. Cranked it over many times and still no fire.
So, I took the cap off the schrader valve I believe it is called and pressed the pressure pin. A tiny bit of gas escaped with about 2 or 3 pounds of pressure behind it. Almost no pressure in my opinion. Then I got my son to crank it over again for a few times, still no start. Then I pressed that relief valve again and got the same tiny bit of gas squirt out with say 2-3 pounds pressure behind it.
Shouldn't there be more pressure at that valve after priming the fuel pump 2 or 3 times, and then cranking it over for say 15 seconds?
I don't have a pressure gauge so that is why I am just pressing the pin by hand.
Do you think my pressure regulator is bad?
When the vehicle first failed to start I detected some gas smell, almost like it was flooded. We let it sit for about half hour in the shop before we did the above testing. Now it seems like not enough pressure. Your opinions??

 

[sholzy]

Pull the vacuum hose off the regulator. If gas comes out, it's bad.

 

[bhawk]

I did pull the hose off. It seemed dry.
However after letting the truck sit for about an hour, I turned the key on and off several times listening for the fuel pump in the tank to come on and turn off, which it did. Then I cranked it over for a fairly long time and it started up and ran okay. Turned if off. It did restart okay.
But I am concerned about driving it that way. It seems to me either the fuel pump or fuel pressure regulator are on the way out.
How can I tell whether low fuel pressure is caused by the fuel pump or fuel pressure regulator?
(I intend to buy a fuel pressure gauge today to do some tests.)

 

[sholzy]

How old is the fuel filter?

 

[bhawk]

I haven't changed the fuel filter since we got the truck 3 years ago. So that is a good idea to start with.
UPDATE: I bought a fuel pressure gauge today. With the key on engine off, after the pump turns off after say 3 seconds, I get 35 psi at the test valve. That is about right I believe. Did the test 3 times and each time I got 35 psi after just on key on cycle.
I haven't tested it running yet.
I am now doing a leak down test. After 50 minutes it has leaked down from 35 psi to about 25 psi. I expect it will go to zero in a couple hours.
What does this indicate? Bad check valve in pump, or leaking fuel pressure regulator?
What if I take the return line off the fuel pressure regulator and watch to see if it leaks fuel with the engine off and key off. Would I be able to tell if I am leaking down pressure there by just looking?
Should a pressure regulator hold tight at 35 psi with the key and engine off?
How long should it normally take to lose pressure from 35 to 0? Is it normal to lose 35 pounds overnight?