Somemedic, thank you for the info! My new M1028 would only idle, die, and drive at a top speed of 5 mph. Cucvfreek spent 4 hours helping me bleed the fuel at the filter, and look for other issues. I was on the verge of ordering a rebuilt injector pump, when I did a final search for similar problems.
I removed the rubber return hose from the top of the IP, unscrewed the nipple, put it in a vice and dropped a 1/8" punch into it - a few raps with a hammer broke the glass in there. Shot brake cleaner through it, then compressed air. Put it all back together, and it fired right up, and REVVED! I got in it and drove 30 miles. The truck hit (indicated) 82 mph!
Thanks to you, Cucvfreek, and all the other guys who post helpful info on this site! I am now an M1028 driver!