2004 F250 Diesel powerstroke 6L - While driving, gas pedal went to the floor, but no power. Shortly after, it shut off. With no power steering, I got it to the side of the road. Changed fuel filters. It cranks, but just won't quite turn over. What now?

Perform the general diesel engine troubleshooting tests in the link below:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-8.html#post1415281

Try starting with high pressure oil and check the icp. Do you have pressure greater than 500 psi? Maybe your engine requires only 450 psi oil pressure at the injectors to actuate the injectors.