Wondered if I might be able to pick everyone's brain a bit. I've searched and read a few posts that have helped but I'm stumped on this one.

I have a '95 F-150 4.9l 6 cyl. Recently it's been idling kind of rough, stalling after start up and bucking while driving. My first thought was vacuum leak somewhere. Pulled the codes and it came up with the following codes:

327
(O,R,M)
EGR feedback signal is/was low – EVR or PFE

332
(R,M)
EGR did not open/respond during test or if memory code, did not open intermittently – EVR or PFE

337
(O,R,M)
EGR feedback signal is/was was high – EVR

I started checking the vacuum lines near the EGR valve/sensor and saw that the EGR Valve plunger had a hole in it, so I bought a replacement valve. Upon removing the old valve, I saw that someone tried a homemade delete with an aluminum can which looked like it had already burnt a whole through to open it up. I went ahead and replaced the valve without a delete. Of course it cleared the codes BUT I'm still experiencing the same problems. . . . rough idling, stalling after start up and bucking when driving. But this time no codes are coming up. I tried to run a KOEO scan with my code reader, but the engine dies as soon as it reads how many cylinders are running.

Any idea what the problem could be? Should I go ahead and delete the EGR Valve? Which would suck considering it wasn't cheap to buy only to delete it. Could it be a timing issue? Any suggestions?

 

KOEO = Key On Engine Off.

I assume you cannot run the Key On Engine Running (KOER) tests?

How old are the plugs, wires, cap & rotor?

 

Yes sorry.

KOEO comes back with 111 - checks ok
KOER - engine dies.

Plugs and wires are under a year old although I did put a lot of mileage on them this year.

Rotor and Cap . . . . haven't changed them.

I did do a Seafoam treatment not too long ago to the tank, crankcase and vacuum. . . although the vacuum treatment was before I changed the EGR valve.

And there is a faint smell of exhaust now and then. Not all the time.

 

Put a new ERG tube I had the same issues with my 7.5 I changed out a lot stuff it was the EGR tube not enough pressure from the exhaust manifold to operate the EGR valve ect.


I know for me the fitting off the exhaust manifold was bad also so check that al;so.

 

I would stick to the basics. Change out that unknown cap and rotor before throwing any more parts at the problem.

 

Fwiw, the egr valve doesn't rely on exhaust pressure at all in order to operate.

 

Thanks for the info Randy. I'll try the cap and rotor first. Didn't think about checking the plug wires . . . wondering if one might just be loose. Either way, cap and rotor needs to be changed.

Marv02, appreciate the info. That will probably be my next option. Tube new at AutoZone is $73.99 so I'd rather hold off on that if I can.

89F2urd, any information is always appreciated . . . my thought is you can never learn enough. Love this truck so I want to keep her around as long as I can.

Anybody else with any more info . . . keep it coming. I'll post some updates as I do some of the work to share with anyone else having similar problems.

 

By the way . . . on a side note. She just hit 200,000 miles last weekend. So I think she's trying to tell me something. Time for a makeover.

 

Okay, so I went to lunch and decided to just look under the hood for a while to see what I could find. Originally, I went out there to check all my plug wires to be sure they were plugged in okay.

They were.

Then I turned it on and took it for a drive around a couple of blocks to see if moving them around made a difference.

No difference.

With the vehicle still idling in park, I disconnected the IAC sensor.

It died.

BUT . . . while I was plugging the sensor back on . . . I noticed this tube coming out of the throttle body.



Could this be the problem?

This shorter one is on the other side of the throttle body . . . obviously looks newer.



Both from the throttle bottle, connect and lead over the engine . . .



To this dohickey next to and under the battery tray . . . what is it?

 

Sorry for the huge pictures.

 

Those lines are for the fuel tank vapor recovery system. There should be a CANP (Canister Purge) solenoid inline to the charcoal canister in the last photo.

This is what it looks like and positioned on a 5.8L:


If the rest of the vacuum lines are deteriorated like those in the photo, do yourself a favor...replace all of them.

 

Hmm, interesting. My engine is the straight 6, 4.9L. The hoses from the throttle body come together and go straight to the Vapor Canister pictured in the last pic. No purge valve. The only other thing I saw that maybe resembled that is located under the the EGR valve on the side of the valve cover. There is a vacuum line going to it but there is also a loose connector that's been there since I've owned the vehicle. Not sure what it goes to.

 

UPDATE: okay so I replaced those lines that were coming apart. Started her up and still had a rough idle. Turned it off and ran a scan and got the following:

KOEO
111
10
111

So that test came back clear of any codes.

This time it let me do a KOER test and I got the following:

6 - number of cylinders
129 - insufficient MAF change during dynamic response test
167 - throttle position sensor fault during dynamic response test
225 - knock sensor fault during dynamic response test

I find it unusual that all these sensors failed. Hopefully I did the KOER test right. Could there be some electrical issue or vacuum issue to cause all these to fail at once?

 

Did you "goose" the throttle at the correct time during the KOER tests? It takes a pretty good stab if you did.

 

I'm going to say probably not being that the scanner I used didn't notify me when to do any of the required items. . . so I just winged it. Going back over the instruction manual . . . . I'm pretty sure I screwed it up. I'll re-do the KOER test today when I get home . . . didn't bring the scanner with me this time.