HELP! Randomly no spark!

Post 3 is good. Also an old trick is carry a glass of ice water. When it quits, dump the ice water on the ECU and see if it will restart. If it does, put an ECU on it. It's breaking down when it gets hot. We used to diagnose intermittent Ford Duraspark boxes back in the 70s and 80s like that. Worked every time.