I had this problem too. When I had my car on the dyno it was running really rich. After that it started smelling like sulfur under normal (slightly spirited) driving. I *****ed to Ford that something was wrong, but their computers told them nothing was wrong. They finally said that my MAF sensor was on the far end of the scale and that they really had to "fight the system" to replace it. After that it has run fine.
I figure my cat is bad now though from having raw fuel in it. Really hard to convince Ford to replace my precats and cat.
