My fuel pressure sporadically changes and considering all the prior investigating I have done, I am wondering if a weak Overflow Valve could be the culprit, or if the ECM is commanding full flow.  Seems my fuel pressure will go up a little AFTER a long pull, like maybe the VP44 senses its brain is getting hot and needs more flow to help cool it.  My fuel pressure sensor is at the inlet of the VP44, which is equipped with a big, long-sweep Vulcan-supplied fitting, not a banjo bolt.

 

I see the procedure for testing the Overflow Valve regulator is on page 14-84 of the manual (1618 of 2939 in the PDF) and seems pretty easy.  Has anyone found this item to be a problem?
I can't find my exploded VP44 diagram to know if this is before or after the internal pump, not do I know if that would really affect my pressure reading.  On the plus side, if this valve is opening earlier and flowing more, that ought to keep my VP44 nice and cool.

I have 10 PSIG even accelerating up hill, and sometimes my fuel pressure will go up to 14 (which almost never happens, even cold fuel at idle).

Most likely the fuel pressure regulator in the lift pump.