Intermittent crank no start

I intended to mention this and someone else did earlier. Have you tried simply jumpering 12V direct to coil +? You don't want to run it this way very long, but doing so might give you an idea of where you stand, IE if it cranks right up and runs, you know you are headed down the right track of low voltage.

Also, "I think" that I know that a .177 caliber rifle brush (same as bb/ pellet) will fit and clean the connectors such as flat trailer connectors, the distributor pickup connector, and the connector on the ECU. You might investigate that.

(EDIT:) Just checked, and yes, a .177 pellet fits snug right into the female terminal of those connectors