P0401 code on 1998 Ford Expedition

check eng. light comes on. Changed DPFE, EGR, Idil air control and light still comes on. Pressley.Rick@yahoo.com

2 answers
egr ports are stoped up in the intake manifold will need to be cleaned out
This could be a DPFE sensor failure too. Cheap and easy repair, at the side of the inake, two hoses and a mounting.