For what it is worth I had one of the almost completely stock lightning's (had a new muffler) that ejected a plug. We had just put an exhaust on it and I was letting my father hear what it sounded like after the change. I started it up and let it idle for a few secs (was already up to temp) and revved the truck to just under 4k and when I let off the throttle it wanted to die. It didn't take long to figure out what the problems was.
This is a common problem and ford is well aware of it. I called the local dealer and spoke with the service manager and told him what had happened. He told me they would be more then happy to fix it and provide me with a car until the L was done. They came and got it. When I got to the dealer they knew who I was and several techs told me it was a common thing and they would have me up and running in no time.

Don't know if that helps but that is what happened to me.



Sorry for the edit I should say save for the new muffler the truck was stock.