Just a note of caution about the OBD II world, don't mess with the EGR except keep it working properly. Those days of blocking EGR doesn't fly anymore, does just the opposite.
I would get a new DPFE and do a search on cleaning the EGR passages behind the throttle body gasket. Very few have ever had to replace an EGR valve itself or find very much build up. It's on the intake manifold passages. If your careful you may not need new TB gasket.
The DPFE operates in a harsh enviroment and every OBD II Ford it tends to fail, not the EGR valve. The new replacement plastic bodied DPFE has increased it's life.
Good Luck it's not tricky to get at if you remove the air box and accordian hose, but then you'll need to that to remove the TB throttle body.
Now you will be able to deal with the O2 more accurately? Cars are not cheap to keep running properly, but if done according to the hints and kinks the CEG'ers have found over the last 8-10 years you shouldn't have to waste too much.
Paul
