I've put about 6-7K more miles on since the new set of plugs and the new ignition coil and I've had no repeat of the problems. It's probably too soon to conclude much since it took 20K miles to run in to the problem the first time.
As I thought about this situation long after the original post, I recalled an aggressive drive on a south Texas beach where I was tearing up the sand pretty good. I was monitoring the engine and transmission temps and thought things were staying reasonably cool, but at one point I got out of the truck, turned the engine off and smelled something that wasn't quite a burning smell but rather what I took at the time to be a really hot engine compartment (resulting from low speeds and low air flow with very high engine power output). I didn't worry much at the time because both the engine and tranny were staying within operational limits, but in retrospect I wonder if the engine compartment itself got way too hot and melted the ignition coil and made the plugs "fragile." Any similar experiences? Maybe our Raptors do have limits after all.
