Engine cranks but will not run on 2003 Ford F-350 Super Duty

Truck started losing power down to 5 mph and now won't crank. I have checked fuel tank, change both fuel filters, checked fuses,bled air at filter on top of engine, has 3/4 tank of fuel. while cranking the oil pressure comes up and engine turns real fast like it is going to run

Asked by for the 2003 Ford F-350 Super Duty
There are many causes of problems with the 6.0L Diesel engine, but my first thought is with a loss of oil pressure to the high pressure oil pump from an issue with a branch tube that mounts to the pump. The high pressure oil pump drives the fuel injectors, and without great high pressure oil, your injectors will not fire well enough to run.