Ford Truck Enthusiasts Forums - 2003 F350 6.0L diesel--replaced fuel pump, won't start

Was returning home to MN from an east coast road trip at the end of May, half-way home, just after refueling, the truck started showing sudden loss of power when starting out from a stop. It ran OK at highway speed, but would die out, re-catch, die-out and re-catch after exiting the freeway, and at speeds under 30 mph or so. Suspected bad fuel, so I changed the fuel filters in Louisville, and seemed to run fine 400 miles or so into northern IL, when symptoms showed up again after leaving the freeway. Nursed it along into central WI, when, just after refueling, it was much worse than ever. I couldn't reach freeway speed, then couldn't sustain 20 mph. Limped along the shoulder into the first exit, found the service station there permanently closed, so limped back up the freeway ramp onto I94. Within a few hundred yards it started working fine again, and we just kept her going the 250 miles to home. At that point, you could hear the fuel pump continually whine underneath the driver's seat, but power was fine.
Ordered a replacement pump (Ford original) and continued to drive the truck around the farm while waiting for the new pump, with minimal symptoms, other than the whine. Finally, the whine was louder on a restart, and it failed within a few minutes, and the truck wouldn't restart. Replaced the pump and filters a few days later when it arrived. Filters looked OK. Truck turns over lack mad--batteries are a month old-- but no ignition. Checked the secondary fuel filter, and the cup was full to within a 1/4" of the top. Can hear the pump quietly running at pre-ignition, so I suspect it is doing its job. Checked fuses, all OK. Disconnected the IGR sensor-- made no difference.
Any ideas?