Yes, I think replacing all is probably the best approach. I did remove the cowling and got the coil out for inspection. My brother had a Buick coil pack failing and it had obvious cracks underneath-I thought maybe the same-but no cracks anywhere. The coil pack is a "Motorcraft". I think this may have been replaced before as this part looks kind of new. And the spark plug wires have also been replaced. As I have said I do not know the history. Money is always an issue but I would be reluctant to get a salvage yard coil pack that may have the same problem soon-especially on a no warranty-no return basis--although that is what my brother did. His had three coil packs mounted on a single bracket so he wound up with spares-and they were right there in front. I am thinking of replacing the EGR device and the coil pack first and see what happens The rear plugs seem to be an ominous task even with the cowling out. Have you done this? Hey Thanks again and all the best your way, Larry

 

Yes, I did the coil first, then few days later I replaced the EGR to be sure I was on the right track. Good luck.

 

My coil went bad at about 65,000 miles. I got a replacement brand one at Advance Auto parts. I figured if the Motorcraft original failed that early, the replacements cant be any worse. I changed out the plugs and wires as long as I was in there. It's not that much more expensive and they probably would need it soon anyways. If you insist on getting OEM, go to fordparts.com and buy it that way from your local dealers parts dept. You will get a discount off the price they charge if you just called them up, and you just go and pick it up after you buy it online.
I didn't mess with the EGR. My 2 cents worth: just fix the coil and see if that takes care of your problem. Save the expense on the EGR..."if it ain't broke, don't fix it".