Man, good suggestions, I'll do some of these in the morning with what else I got planned, which is...

Remove the truck bed and rebuild the fuel pump assembly.

Don't scream at the computer, I know, I know...

Can't remember how many years ago it was rebuilt so might as well do the preventive maintenance even if it doesn't sound like the culprit. But, if it's seizing, that would explain the extra battery voltage drop at all the times the pump doesn't start, which is the main thing stuck in my head.

Also, it could be a blocked return as Bluegrass suggested. With the bed off I can more easily do a volume and pressure test on the entire return. Of course check all the electrical as well.

If all this doesn't cut it then perhaps Monday or Tuesday will be battery swap day. Hopefully an Expletive Touretts Day will not happen afterwards.