OK I was talking to 3 friends that work at 3 different Ford places near here. All gave me the same info. They have seen hundreds of air box problems. Although Ford will not say they have a problem.
1 the air box material is made to thin.
2 there is not enough surface area to the filter.
So when the filter gets dirty the hugh amount of air needed by the PSD deforms the air box allowing unfiltered air in.

Ford is hiding behind a legality on this one. They are saying that the air box will not deforme if the filter is kept clean and that is part of the owners job. So it is through neglect of the owner by letting the airfilter get dirty that the problem presents it self.

Now you do not have to agree that Ford is right, and I don't, but you better make sure you keep a new filter in the truck at all times or it is gona cost you a ton.

Also the Tymar ?sp was build so that it has much more surface area and so if it is let go to long between changes it can still pass enough air.

I know Ford screwed the pooch and you know they did too but protect yourself because they are not going to. All 3 told me Ford said on every occasion that it was the Owners fault! and did nothing.