Fuel Injectors not working?

I have a 1998 Ford Explorer 4.0l, automatic. The fuel injectors are not working, i used a noid light on all of them, the light did not blink on any injector while cranking the engine. I have power to the injectors with the key on. A friend that works for Ford told me CMP sensor, i replaced it and still nothing. I am lost on this one. In the past month it has started a few times, but the next day will not start. It has spark it will always fire with ether, but wont start! Any ideas on this one?