P0401 code on 1998 Ford Expedition

check eng. light comes on. Changed DPFE, EGR, Idil air control and light still comes on.

Asked by for the 1998 Ford Expedition
This could be a DPFE sensor failure too. Cheap and easy repair, at the side of the inake, two hoses and a mounting.
1 more answer
egr ports are stoped up in the intake manifold will need to be cleaned out