DPFE = Differential Pressure Feedback EGR sensor. It has 2 short hoses that come from the exhaust manifold-to-EGR tube. On your car it is mounted on firewall at about the center of car (if Fig 6.26 in Haynes manual is accurate).

98 Mystique LS v6 atx 163,000km 97 Contour LX v6 atx 163,000km