Originally Posted by expeditiondevil

Ok so not 'modules' but module. I've had the powertrain control module replaced as the Ford dealership thought that was the problem at one time. It did fix it but three weeks later the #3 went out. It didn't make sense that that module would only be affecting the coils. Who knows.

I'm taking it to a new mechanic on Monday that I heard has had some experience working on these. I'll talk to him about scoping the primary side like you say and see if it might have a tell-tell sign of what might be making these blow out so quick. Almost like a surge or something that is maybe producing too much voltage on them. Thanks for the ideas.