Im new to the forum and have been looking nonstop for a clue as to what's going on. I had to let my truck sit for a good amount of time due to unforseen circumstances. Went to go start it the other day and it's running awful. It was idling kind of rough, and when I went to put it into gear it idles really rough and vibrates the whole truck. I thought at first that it was just bad gas from it sitting for so long (about 6/7 months), and maybe gummed up injectors. So i filled it up with new gas and seafoam, and no improvement. It doesnt seem to be a vacuum leak as i sprayed the crap out of every possible vacuum line I could find and nothing. I took it to autozone and it threw the following codes:

P0174 Fuel system too lean (cylinder bank 2)
P0356 Ignition coil 6/F Primary/Secondary circuit malfunction
P0405 Exhaust gas recirculation sensor A circuit low
P1405 DPFE sensor upstream hose off or plugged
P0306 cylinder number 6 misfire detected
P0316 Misfire in the first 1000 revolutions

Im completely at a loss. I cant think of why only one bank would be running lean like that. Could it be that maybe bank 1 is running lean as well but not throwing a code? Its also sounds almost like a diesel when cold. im not super mechanically inclined nor do i have the proper tools to diagnose the problem on my own, so any help would be great. Im scared to drive it without getting it fixed, but its my only vehicle at the moment.

its a 2002 f150 screw 5.4L 2wd

 

First things first fix your cylinder six misfire. It will be the third back on the driver side. Also check your plug wiring and be sure it's intact. New Motorcraft platinum plug and coil would be preferable. Check your dpfe sensor and both hoses off of it. It will be on the driver side of your throttle body.

 

Thanks jprevat. May not be able to fix the misfire at the moment but i at least found out that the DPFE sensor has a peg that broke off and one of the hoses is torn open. Once i get these couple things dealt with we'll see how much of a difference it makes.

 

Ok. So i figured the lean code P0174 might have been from a bad MAF sensor. I cleaned it, and nothing changed. It still idles like garbage. I have a feeling that the misfire and coil codes P0306, P0316, and P0356 are most likely from a bad coil or plug. Im thinking that maybe the EGR code P0405 is maybe just a bad EGR valve. I know that the DPFE sensor has a peg broken and the hoses are torn, probably the only reason the P1405 code came up. I'm going to replace all of them, and hope to god it runs good enough that i can clear the codes and drive for a while and see if they come back. I have a theory, and correct me if I'm wrong.

My theory is that the P0174 code is from cylinder 6 misfiring, allowing unburned air/fuel to go past the O2 sensor, tripping it out and making it think the ratio of air to fuel is too high, causing a lean code. That, or I just have a quiet vacuum leak somewhere that's giving me the worst headache ever. What do y'all think? Lol

Im also curious about wether or not a stuck-open EGR may be causing the lean code.....

 

DPFE has nothing to do with the way it runs, just so you know.

Good luck.

 

Go to a salvage yard and grab a dpfe and get your hoses from rockauto.com. I would probably grab a couple coils too just because they will sell cheap and chances are I'd you get one from the front two cylinders on the motor it will work. You can pull and egr and clean it but if I went through all that trouble I would be putting a new one on.

Your vacuum leak is the dpfe hose and your misfire isn't doing you any favors.

 

New DPFE's are cheap enough, might as well get a new one. A junk yard DPFE will probably be to corroded inside. Those sensors corrode inside from sitting. Reason why I wouldn't chance an old one. They go bad in vehicles that don't get driven much. But yea, those hoses are silicon specific, needed to take all that heat lol. Anyway, I would use new stuff DPFE.

With the OP's DTC's, he has a completely dead hole in #6. Ron, if your driving the vehicle, disconnect #6 injector until you fix that misfire. Otherwise you stand a very good chance melting you cat shut, if you haven't already. It happens quickly, then you'll need to invest quite a bit more fixing the problem. Raw fuel will ignite creating a flame thrower event when pumped into the converter by the exhaust stroke. Melts the advanced coating on the honeycomb melting the cat completely shut. Once that happens, first it melts the hoses on the DPFE and destroys the DPFE. All that is the reason why you handle the misfire first or at the very least , -disconnect that injector pronto.

 

Ill do that right away jbrew. Im fixing to pull the EGR off and clean the living hell out of it to see if it helps. I gotta drive this thing til i get paid later this week. To disconnect the fuel injector all i need to do is remove the harness right?

 

Sounds like your coil pack went out. I had only one cylinder go out on me once while driving (suprise, #6 as well). The truck had sat up for a few months prior to this episode as well.

 

That is right. Those dpfe hoses are like 5 bucks but if you can't spare it wrap that thing in electric tape. Generally I wouldn't say that but if you replacing the dpfe it doesn't matter.