Ford Repair: 01 Sable--- EGR problem, dpfe sensor, exhaust gas recirculation

Question
I have a 01 Sable,71000 mi, 3.0 Vulcan. Code PO401 EGR Flow Insufficient. Also, could be unrelated but at approx. 30 MPH I notice a slight surge. Question:  Should I concentrate only on EGR or is there more parts to check?
Thanks for any help in this matter.

Answer
replace your  dpfe very very common problem , unless u have a scan tool and you can read pids , and your dpfe pid should read 1 volt , if no scan tool i would take a shot with the dpfe sensor, the sensor is off teh back exhaust manifold , there are 2 tubes comming of manifold and then 2 hoses to a sensor that is teh sensor dpfe = defferentail presue feedback exhaust gas recirculation sensor