EGR issue

[Dobbs]

New to posting so I hope I’m explaining my issue so you can possibly help.
I have a 2004 Ranger with a 4.0 and getting PO401, 402 codes. I have foolishly tried to just throw parts at it hoping it would resolve it, NO!
I finally smartened up and started what I think is a good diagnosis process.
I believe I have two problems or one that is causing both.
EGR insufficient and excess flow
Possible vacuum leak
The symptoms are hesitation at off-idle and fluttering at 3000 rpm.
I’ve replaced the EGR, EVR, and DPFE, my proper diagnoses now finds I have bad voltage readings at the DPFE and I can’t find a vacuum leak.
I still have the issue, can anyone help?

 

[lil_Blue_Ford]

Best way to look for vacuum leaks is with a smoke machine.

Voltage issues means you have to trace the circuit and find what is causing the problem. Theoretically your computer is new enough not to have bad capacitors, but it probably wouldn’t hurt to pop the cover and check. Those can cause all sorts of weird issues.