I seem to have a fuel pressure problem as it takes a few seconds for all cylinders to fire when I start the truck. My questions are:

1. Does the fuel pump hold the pressure in the fuel lines when the truck is not running?
2. When a fuel pump goes bad, can it be gradual thing or does it just stop working?
3. Does the fuel pressure regulator hold the pressure in the fuel rail/lines when the truck is not running?
4. When the truck is not running, can fuel injectors start leaking and therefore causing the loss of fuel pressure?

This is on a '91 6g72 motor.

Any help I'de appreciate.
Thanks.

1. Does the fuel pump hold the pressure in the fuel lines when the truck is not running?
It should
2. When a fuel pump goes bad, can it be gradual thing or does it just stop working?
yes
3. Does the fuel pressure regulator hold the pressure in the fuel rail/lines when the truck is not running?
It should if the pump is not back leaking and the injectors are not leaking
4. When the truck is not running, can fuel injectors start leaking and therefore causing the loss of fuel pressure?
yes

The fuel system is a loop, with a pressurized section from the pump to the pressure regulator. The filter is in the pressurized part. Most pumps have some kind of check valve. The regulator should hold the spec pressure. The injectors should not drip at the rated pressure.

In a pinch, I've used a hand vac pump to test injectors (on the pintle) and FPR's on the outlet pipe. I've successfully culled thru JY injectors that way. The only definitive test is to put a pressure gague adapter on it at the fuel rail inlet and watch the gauge on shutdown.

I wish I had looked into this before I posted. It was acting like it was starving for gas, but, I just discovered the problem.
I think I have a blown head gasket. I'm losing water out of the radiator and discovered a small amount of white foam on the dipstick. This is the first time I've seen that. It must be a very slow leak into a cylinder. As I said, It only acts up at startup. Apparenty, as the motor warms, the water is actually burning off in the cylinder and the truck runs fine. I also noticed exhaust fumes/smoke coming out of the radiator and can hear it "bubbling".
Anyway, sorry about posting before I did any real investigating.
Thanks.
Jeff