Ford has DPFE trouble on a lot of their cars, not just the contours. I just bought one for my 2000 taurus a couple of days ago. I'm getting a CEL reading of EGR low flow. Ford had actually extended the warranty for the DPFE on the taurus, but I was still slightly over the limit. From what I can read, it seems that part of the problem is not the sensor itself going bad, but rather gunk getting inside the sensor through the tubes.
I also swapped the DPFE on my mystique yesterday. I pulled the sensor, and looked inside. It was totally stopped up with gunk. I then pulled the DPFE off of my wrecked contour, and it looked a lot better, so I swapped it onto the mystique.
