[Richard and Rhonda]

Let me replay what I think you said. The engine turns over just fine, just doesn't fire. Does it try to fire?

In some ways, diesels are easier to diagnose than gas engines. Fuel and air are the keys. Since it runs fine when it does crank, I am thinking fuel. If it doesn't stumble when it's misbehaving, I think the fuel shutoff solenoid isn't opening. That could be a relay or a bad connection. Is there any way you can slide it out and observe the fuel solenoid while someone else hits the start switch?