engine will not start sometimes on 2006 Dodge Ram 2500

spin engine over trys to hit but wont start,can continue to spin engine and it will crank, can also cycle key off,then engine will crank

Sounds like you're trying to start the engine and it won't start. "Cranking" is what the starter does to spin the engine so it will start. If a Diesel cranks and won't start, there's no fuel getting injected into the combustion chambers. Find a Dodge or Diesel specialist and get it fixed.
If you want to find a specialist, here's a directory ink for you: