This is for a 2001 F150 auto 4x2 with 154,XXX miles. The CEL popped on a while back and listed below the codes are the items that have been replaced up to this point. (Anything not listed is still factory)

I've been digging around a bit to try and find answers, and I've found (I hope) what the list of codes below mean, but I was wondering if this particular combo jumps out at anyone as the failure of one component vs. another, or would be indicative of something specific. As far as repairing these issues and getting the CEL off, where should I start? The truck has plenty of life in it, runs strong, (despite the laundry list of codes) no leaks, has a good body, and trading isn't an option now; in other words, what should I replace first?

The OBD codes are:

-P0305 -Cylinder 5 misfire
-P1401 -Emissions control failure
-P0171 -Bank 1 too lean
-P0174 -Bank 2 too lean

So far, I've replaced all 4 O2 sensors, replaced plugs and wires, cleaned the MAF, and repaired a couple vacuum leaks. I thinking the next steps would be:

DONE -Pulling #5 and visually checking plug and cylinder
DONE -Checking the ignition coil for obvious external cracking or damage
-Replacing the DPFE sensor
-Replacing the EGR valve

Thanks for your help, I can't seem to get the CEL to turn off.

 

Disconnect the negative battery terminal for at least 5 minutes to clear the codes. If the light comes back on, get the (new) codes read out and go from there.

 

I've tried that on numerous occasions, the same codes keep popping up. The miss is nearly constant. After pulling that plug, nothing seems amiss, no oil or coolant smell, next I'll pull the coil and see how that looks, I've read of a few cases where cracks have developed in the underside, I'll check that and see how that looks, then have the codes read again. (battery has been disconnected for a few hours.)

UPDATE: After looking at the coil, it appears fine, although I did notice some chaffing on the #5 plug wire. The grey outer insulation was worn through showing green underneath. These appear to be OEM replacement wires, could that be causing the misfire?

 

Replace that plug wire - if it still misses, replace the coil pack. Get that #5 misfire cleared before you tackle the other codes.

The other codes may be EGR, DPFE, and/or PCV related - and you may not have found all your vacuum leaks.

 

Well, the other codes were there months before the misfire, that's a new one. The wire will be first, followed by the coil if needed, but I suspect the other issues will still be there. I have another week before the truck is needed, so I have some time, but given the price of the DPFE at the local dealer vs. online sources, I will have to order the sensor sooner rather than later if that is indeed part of the issue.

The shop that did the plugs and wires checked the PCV and then moved on to vacuum leaks and seems to have caught all of them. The truck ran fine minus the CEL for a while, so I suspect that it may be EGR or DPFE related, as they didn't diagnose those once they cleared the other issues. (I think the shop that did the aforementioned work bent a bracket above the coil, pushing it down and chaffing the wire... grrrr....)

Does that sound reasonable?

-IKE

 

even a small rip in the plug wire can cause problems like u describe. i was chasing a misfire on my crown vic and it turned out to be a worn plug wire.

 

If you replace the DPFE, get it direct from Ford, the aftermarket units are not the "improved" models. Yes, I know it's expensive.

 

I've already found it at Ford Parts Online (Sherman, TX) for $50.94 with shipping. A local dealer wanted $81.88 plus tax for the same part number! The guy who gives me the shop discount wasn't there today....

ON EDIT: I understand you can test the EGR valve by applying vacuum to it. I'll look up the detailed instructions to test it before ordering the DPFE, but my question is how to apply vacuum? I don't have a pump or anything I can think of to do this; what could I use? (It may show a way here on the forums, but I thought I'd just ask the question direct.)

 

just a thought, but cant you just remove the tube coming from the exhaust and put your finger over the hole when the truck is running.

 

The tube coming out the top? I did try that, but nothing happened. From what I have read, you have to apply vacuum to it, which I am assuming this does not do. (I haven't really looked to see how an EGR valve works, so I don't know if simply blocking that port "applies vacuum" or just cuts off the flow... I don't know enough about them, but it seems that alone wouldn't do it.)

I did replace the chaffed spark plug wire, and the miss is indeed gone, so it looks like the coil is fine for now. Everything I have read on here, in books, etc, would seem to indicate that it is the DPFE valve, so I'm pretty confident that is the issue, I just figured I'd check the EGR first to be a little more sure before I drop the cash.

My first car was a 1966 Chevelle; one day I tuned it up and it ran like crap, so I opened a book and read about timing, dwell, points, and all that fun stuff. My dad had a dwell meter, so I hooked it up per the instructions and made the adjustments. The same with the timing. I basically taught myself everything I needed to know that day by reading a book and doing what it said without knowing what a lot of it was when I woke up that day. A couple hours later, that motor ran like a champ. It's too bad that we have come so far that when something craps out, it's not usually a matter of making an adjustment or something simple (read that as "cheap") but rather a $50 to $80 sensor or two (or a dozen.) Oh well, if a new DPFE solves the problem, it's worth it.

Thanks for the help thus far, and if anyone has additional suggestions, go ahead and post them here, it's sure helped me.

 

Are you sure your PCV hose isn't cracked?

 

I believe that would only cause a rough idle. My GF's focus had a rubber elbow that cracked and it only idled funny and wanted to die when coming to a stop, but no CEL.

 

No, the shop checked the PCV valve and replaced the cracked hoses; based on what I've read elsewhere, read here, and those I have talked to, the DPFE seems to be the suspect. I won't know obviously until I get it here and replace it, but if there are still issues, I'll deal with those when the time comes. Maybe they missed a cracked tube or hose, but I'll resolve that in due time. (I think they got them all)

 

Well, the DPFE sensor fixed the problem... it's taken a while to post because my sensor took a cross-country trip before it got to me. Instead of coming to St. Louis, where I live, it went to Alabama, where I don't, due to a data entry error at Bob Utter... It seems they transposed the first two digits of the zipcode, so I now know the zip of Montgomery, AL! Anyway, that's not a slam on Bob Utter at all, I've ordered many parts and this is the first issue (and not a big one at that) I've ever had, and it was resolved. Still a satisfied customer.

After replacing the DPFE, the truck runs well and I've moved on to the rear u-joints to get rid of a vibration at 35 and 70 mph...

I have a question or three...
-the new joints are greasable, can you use regular brown chassis grease in them, or do you need some high temp, high dollar stuff?
-should I use thread locker on the shaft to axle flange bolts? I'm assuming so, since it looks like the factory did...
-third and final question, should the splines be lubed where they go into the rear of the tranny?

Thanks for the first round of help, the truck's fixed, and thanks for any help on the second go-around!

 

1. Use "EP" grease. I use this stuff for everything, it's $5.50 for a 14 oz cartridge that fits standard hand grease guns, I assume other manufacturers have equivalent:

http://www.amsoil.com/storefront/ghd.aspx

2. It probably wouldn't hurt, observe torque specs.
3. That probably wouldn't hurt too.