Great post!I would look at replacing the #6 coil. I have a 2013 3.5L with 210K miles on it of which I put all 210K on myself. I replace the plugs and caps every 50k miles and am still running with the original coils. If the codes point to #6, well, #6 is where I'd start. After replacing the coil if the code is still coming from #6, look at replacing the #6 plug, and yes, they can be defective/bad out of the box. I've always checked the gap out of the box, but they seem to always be set correctly. I would also look for trash and crud in the cap and around the plug. The mechanics aren't always the best at checking for this.
Mostly because it's always nice to hear from a high mileage Ecoboost owner, and especially if they are the original owner.
Gotta ask...... Why did you suddenly decide to speak up? Lol
You've been so quiet for a loooooong time.
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