I had the same problems,
My converter clogged up, the pressure caused the piston head to go through the engine wall.
It happened to me about 2 weeks ago, and I had an engine purchased for $1500 Canadian and put into the 2002 escape, I also had the converter closest to the muffler replaced, as this was the severely clogged one, and I had another one replaced as well due to a small crack in the casing.
I had it all fixed within a week, and It's running beautifully... I didnt go for the $800 replacement converters from ford though, I purchased 2 aftermarket converters which are designed for the escape... at $250 a pop, i'd much rather go for those. | 
