If,,,,,,,,,,,,,,,,,,, you are SURE it is a no spark situation you need to go down the line of where the signal starts and goes until it gets to the spark plug. Until you do this you can keep replacing things hoping you hit the problem, don't forget there is always that darn possibility of installing a NEW defective part, which if you did not prove the part you just replaced as being defective. There are tests that you need to do and that require special test equipment and sometimes are best left to the people with the tools .