I am in the process of diagnosing my fuel system to remedy a warm motor, slow start condition that is pissing me off. Motor starts perfectly cold and runs well otherwise.

Fuel pressure (basic motor running test) at the rail is 40# and 44#. No issue there.

I have plumbed my fuel pressure gage into the fuel filter outlet for direct pump pressure testing. This takes the FPR, lines and the injectors out of the picture.

I turned the key and set the initial pressure to 50# which is as I as I could get it. I am thinking there is a 50# MAX pressure bleed off at the pump since I cant get any higher than 50#. Is this correct?

It bled off to 43# in five minutes. It then bled off to 17# after one hour. Does this indicate that the fuel pump residual pressure is in in out of spec? What is the correct spec?

I have also pulled the rail to inspect for leaky injectors or leaky FPR. This was done by pressurizing the rail and watch for leaks while it is off the motor.

There is no leakage from these two parts.
Clearly the check valve in the pump is letting it bleed back into the tank some. I just want to know if its in spec or out of spec.