I have a 99 f350 v-10 that won't start. It was intermittent at first and now it won't start at all.

It turns over fine but will not fire

I have replaced the fuel filter, fuel pump, crank and cam sensors and the battery.

The plugs were replaced 18 months ago. I have not put 5000 miles on the plugs since replacement them.

I am at a loss for what to do next.