When my engine light first came on, I took it to autozone to check the code and they told me I need a new catalytic converter, I asked them the code, (P0401 it was) and they showed me on their computer only Cat or exhaust issues came up. expecting an autoparts store would be trustworthy, I decided to ignore it until I need my inspection and wait to get a new cat. recently, My positive battery terminal which is frayed at the end comes loose and my truck wont even try to turn over so I gotta get out and wiggle the wire until the hood light comes back on. When it does start, It kinda doesnt wanna run until I give it some gas, then it runs fine. So the engine light goes off which was odd I just figured my positive terminal just hasn't been connected long enough for the ecu to read. well I got an OBD II scanner and scanned it when it came back on (after Fixing my terminal) and it came up with the same P0401 Code which the book it came with and the internets say is insufficient egr flow. Upon startup, its having the same wanting to putter out and die issue before it runs but its not everytime. Any ideas/suggestions? Is it just a sensor or an EGR valve?
and if its any help-
1996 4.9 I6 M5OD 5sp

 

I have not worked on any obd2 non modular trucks, so, if I'm wrong, sorry.

The insufficient flow could either be
Egr valve stuck
Or
Egr flow sensor gummed up.

Egr not opening is sometimes it
Sometimes there is a flow sensor that takes a sample from the egr tube and then returns it about 3" higher then it took it from. That gets gummed up and throws that code. Or the rubber hoses rotted/burned off.

 

Hm.. I wonder if cleaning the tubes would help

 

Pull egr valve off and clean it. Spray carb cleaner in and get rid of as much black crap as you can. Pull hoses off flow sensor and spray cleaner into there also. Let soak and gently blow out. I don't know how it works so don't just blast air into it.

 

Common causes of this error are cracked EGR tube, plugged or cracked DPFE sensor hoses, faulty DPFE sensor. The hoses are made of silicone but they do degrade after a period of time. They tend to crack more if you start moving them around.

I found Standard Motor Products carries a replacement pack of hoses under Part No.# M40001.

A video for troubleshooting Ford P0401 errors: Ford P0401 DPFE EGR Pressure Sensor Diagnostics and Repair with a Contest - YouTube