6.0 Sporadically not starting
 

I have a 205 f350 with a 6.0. I replaced the batteries and the alternator but I am still having sporadic issues with it not starting. Lights flicker, dim displays. It will jump start after a few minutes of being hooked to a running car. What is weird is that the problem is very sporadic and happens on cold starts and after lengthy running times.


Thoughts?