Odd fuel pressure issue

I have owned and worked on this vehicle for years, and as you know, failing fuel pumps on these are a fairly regular occurance. I am familiar with the correct pump pressures, etc, but this time it is quite odd.

The pump quit working a few days ago. I replaced it per usual, but then discovered that the wire coming back along the frame had worn through and failed at some point along the way, so I ran a new wire between the output of the fuel relay to the hot of the pump, which solved the problem and the car ran fine.

A couple days later, the vehicle became hard-starting and running rough. Believing I had stirred up sediment that had probably clogged the in-line fuel filter (which was more than 5 years old anyhow) I replaced the fuel filter, and it immediately started up and ran perfectly.

After a few hundred miles, it began to become hard starting again, but when it did start it ran fine. I have checked the fuel pressure, and I am getting 60 lbs. On the prime, 55 lbs while running, but only about 45 lbs. While cranking. After shutting down, it jumps back to 58 lbs, then bleeds to 52 lbs after 3 minutes and down to 38 lbs after 10 minutes.

I am thinking that the 45 lbs. During cranking is from additional sediment getting into the new fuel filter, and I plan on pulling it to back flush and test again. However, my question is do you think the odd fuel pressure readings might indicate a different problem? It has been my experience that if it was a bad pressure regulator or injector the pressure will bleed to zero within a minute or 2 of turning the motor off.

Please let me know what other issues you think are more likely, or if you also think it might be the new filter clogging a bit.