Is there a way know which coil is going bad before the check engine light comes on? I have one or more going bad but my trucks still running strong enough not to throw me a code.

 

bump

 

I was going to tell you to swap them and chase the code...but no code...

 

If it's not tossing you a code, there's no "easy" way to tell if it's going bad. Maybe the Ford techs have a device that can test them, but I've not heard of one that the average home mechanic can get. A simple multi-meter would not work, as the coil whould need to be under a load to test it correctly I'd think.