2000 7.4 vortec no start consdition

i have a 2000 454 7.4 vortec in a trekk rv

the motor stopped running while driving down the highway.

1 fuel pressure is 55 and only drops 10 psi over 5 hours time.

2 got spark at coil and spark plugs

3. swapped relays around to make sure that was not the problem.

4.engine cranks normally not to fast or slow from normal before problem acoured

so anyone have any ideals what i need to look for or know what it may be from prior problems you may have had with this engine?

mno trouble codes in computer after it died or presently

Fuel pressure may be too low, spray carb cleaner into the intake see if it starts momentarily.

Fixed turned out to be some very bad spark plugs and one broken plug wire whe purrs like a kitten now