One of the easiest ways to diagnose a problem between ignition, and fuel is to simply hook up a timing light. I found out the no start on my 216 right away when the light didn't flash while cranking. It was the points. You can even rig it up to check while driving with intermittent problems putting the light inside the cab. Same for fuel pressure, but not inside the cab. Ethanol fuel can do crazy stuff too.
