1997 Contour V6 2.5 litre Duratec(Canada). I had PO401 code come up on my code reader.EGR exhaust insufficent flow. Someone suggested DPFE sensor or EGR valve solenoid. Others suggested blocked EGR tube before or after EGR valve. I followed one members advice and removed the throttle body for inspection. Boy! It was gummed up pretty Good. I cleaned it up and all ok.
I took some photos if anyone is interested drop me a line and I'll send them onto you!
P.S. A good article available on DPFE/EGR system sensors
at
www.smpcorp.com/download/view/tt2q00.pdf 
