The right way to find the fault is with an in-line spark tester, Aldo:
http://www.ebay.com.au/itm/633982-S...arts_Accessories&hash=item540cdc26c2

Once you've overhauled the ignition system as you have, the next step is to see whether it really has steady even spark when it is misbehaving. Once you know it is ignition failure, you need to isolate the kill wire to be sure that isn't where the breakdown is occurring, before you consider the ignition module itself.

You don't need to buy the in-line tester if you'd rather make one. Here is a type that's easy to make:
http://www.ebay.com.au/itm/motion-p...arts_Accessories&hash=item4155d959a2