ok, i had a code number 335, 336, 337 on my truck for months. so i changed the dpfe and the cel stayed off for 5 days. today while driving, the light came back on. i scanned it again and got a code 327.

327 - egr valve position circuit below minimum voltage.

327 - evp/ept circuit below minimum voltage.

so either the egr valve or the evp/ebt is bad, right? how do i know which one?

1994 3.0 supercab 5-speed