During Christmas, I lost two coils simultaneously. It appears to have occurred when I went to two wheel drive from four wheel drive. I thought it may have been coincidental so when I got my truck out of the shop, I put it into four wheel drive then back into two wheel and the truck started to miss and about 30 minutes later the check engine light came on. Taking it back to the shop, one coil was bad on the same cylinder as was previously replaced. The repair work was not done at a Ford dealership.
Is it possible switching from four wheel drive back to two wheel drive could cause a high voltage current to the coil? I can't believe two coils would go at the same time unless it is related to some other problem. By the way, I have kept the truck in two wheel drive since replacing the last coil and it is running fine.