Originally Posted by Ahsai

Did you notice if the tach needle bounces when the no start happened? If it does not, it points to the crank position sensor. If it does, it's not conclusive.

My next guess is the fuel pump and fuel filter. You may need to check the fuel pressure when it doesn't start up. Do you hear the fuel bump priming at all when no start happened?

Also have you cleaned the idle stabilizer and throttle body?