Greetings!
So I pulled my EECIV codes, and would appreciate any help in de-coding them. I did go to the "Look here first" area, and clicked link to the Oldfuelinjection.com website, which gave me 1 of the 3 codes:
I pulled(KOEO):
--395
--391
--334 (DPFE or EVP circuit above the closed limit of 0.67volts.)

I'm getting lousy mpg of about 6, which is surprisingly 40% lower than my typical 10mpg from my 7.5L--which I never thought I'd miss~
The engine 'stutters/stalls at around 3200 rpm/60mph...but seems to go away if I accelerate through it, or drop a gear and reduce speed. It is an intermittent problem (most fun to diagnose) and I suspect the TPI sensor is bad, although I thought best to run codes first, before banging my head against the hood trying to remove the two 'bolts' holding it in place.

Many thanks for any thoughts/input.

 

What year/model/engine/transmission truck are you working on? How did you "pull" the codes? My Ford service manual does not list Codes 391 or 395 either.

 

Sorry, thought that was part of my post.
1994 F350XL 460EFI ZF5
I ran a jumper wire from/to the EECIV "plug" near power bake booster area, then Key on, Engine off, watched the check engine light flash the codes.

 

Codes 391 and 395 are not listed in any of my 1992-1997 Ford truck service manuals. I am not sure where to point you other than re-checking the code flashes. It can be tricky to decipher the flashes.

 

Thanks for your input un confirming unavailability of those codes-It's comforting knowing people give a damn these days.
I ran the codes 3 times, same results. Maybe I have the jumper lead on the wrong slot...will advise.

 

I went back and tried to do the whole process over to see if somehow I'd caused the codes to pop up. Oddly enough, when I follow the directions from oldfuelinjection.com, and just run a ground wire to the "STI"-Self-Test Input, I get no codes, no flashing of the check engine light, etc.
Initially, I'd watched a video on Youtube to get a better idea of the process, and followed those instructions for EECIV code reading...which differed slightly from the link on this site in that it showed running a wire from the STI not to ground, but rather to the SIG-RTN slot of the EECIV testblock. This is what I'd done to generate the initial codes listed in this post.
I reconnected the wire to the SIG-RTN slot, and ran codes three times again. Now I'm only getting code 334. Think I'll search for posts on that, maybe pull the PCV valve, scrub it down with carb cleaner, and check again.

 

My book says code 334 = EGR closed valve voltage high
I also have a code reading tutorial writeup - link in my signature.

 

X2...Code 334: EVP circuit above the closed limit of 0.67 volts. Use a DVM to verify the EVP signal output. A common cause of this code is a EGR that cannot fully close because of carbon build up.

EVP info: Fuel Injection Technical Library » EGR Valve Position sensor (EVP)

 

Thanks for the followup...going to attempt EVP signal test, & may just pull EGR & spray n scrub carbon residue off best I can. Will advise.

 

I had code 334 pop up on one of my '93 Lightnings. The truck would not idle, but running down the road it was fine. Of course it happened on a 600 mile round trip. Once I got back home I found a piece of aluminum casting stuck in the EGR pintle. Good thing it wound there instead of inside the engine.