Need help - Engine Error Codes

[KaiserM715]

So after going wheeling this past weekend ( http://www.explorerforum.com/forums/showthread.php?p=1344818#post1344818 ) I start my truck on Sunday to go home and get a check engine light. I took it by Autozone today and had them check the codes and here is what they came up with: P0171 - P0174. Here is what the Autozone guy told me: one of the codes corresponds with one engine bank, the other code corresponds to the other engine bank.

For the single engine bank codes here are the possible problems:
-O2 sensor defective
-Ignition misfire or vaccum leak
-Fuel injector problem

As I have those possible problems for both banks, that also adds the following possible problem:
-Fuel pressure or mass airflow sensor

I looked up the codes:
P0171 System too Lean (Bank 1)
P0174 System too Lean (Bank 2)

My truck has about 60k miles (4.0L OHV / Auto). I am still on all of the original engine components listed above as well as the original fuel filter (on my to-do list). The guy at Autozone sure was trying to sell me some O2 sensors saying that they are only 50k mile parts, yet I have never replaced one on any of the vehicles I have owned (two of which had 100k+). Does anyone have any thoughts? I am going to disconnect the battery tonight to see if I can get the codes to reset.

Thanks for the help.

 

[Runnin'OnEmpty]

M715, since both lean codes showed up at once, and from a cold start, I'd say they're caused by the infamous intake manifold leak.

I've heard that the intake O-rings have been revised recently by Ford, so maybe replacements will be better than the originals......

ROE

 

[KaiserM715]

Are the O-rings that you are refering to in between the lower intake and the heads or in between the upper and lower intakes? I am guessing the latter. Thanks for the input.

 

[Explodersport]

yeah, I had the same problem come up. except mine came up seperately. I got one a week ago (p0171) and then the other came in today (p0174). I also got another code I am checking out now too. It is the p1405 which is a manufacturer specific drivetrain code. Yikes! gonna look into it a little further...

 

[KaiserM715]

I disconnected the battery and let it sit for about an hour and reconnected it. I started it up and no CEL. I guess water got into something this weekend and the computer didn't like it. I will check later to see if it comes back.

Thanks for the help.

 

[Runnin'OnEmpty]

M715, glad the light went off. If it comes back on, I'd snug down the intake nuts and see if that helps, before removing the manifold. The O-rings I referred to are on the bottom section; there's a conventional gasket on the upper. If you do decide to replace them, check with a dealer to verify new ones have indeed been revised. Good luck.

ExploderSport, P1405 refers to the DPFE sensor upstream hose being off or plugged. I'd check the hose, I'll bet it's come loose, or maybe cracked......

 

[Explodersport]

on my agenda this weekend is to check that out. I just finished finals, so my brain is mush and ready for some car work. Hopefullly I can fix all of these. Anyone knows what I should do, lemme know.

 

[spindlecone]

Ck a few posts down before ripping things apart,might be an easy fix

 

[Explodersport]

so far the trend seems to be the manifold o-rings and the hose. 2 questions, where is this hose I need to check and where are the o-rings I need to replace? Any idea of how much $$$ they cost? Alright, so it was 3 questions...

 

[spindlecone]

Ck my post of 45 mins ago

 

[Explodersport]

yeah, so I went out this morning to try and find the problem.... well, I guess I had a run in with the blowtorch fairy. prolly 30% of the DPFE is in a puddle on the wiring harness underneath. I couldnt even find the hose that connected to it, turns out it blew the tip off and fell underneath the intake, so I dont even know the damage that is under there yet.... I got pictures but I dont know if I can post them, if someone else can i will send them to you. Could this take care of my p0171 and p0174 codes too?

 

[Runnin'OnEmpty]

Could this take care of my p0171 and p0174 codes too?

There's a very good possibility, if you have an intake leak through that EGR meltdown.....

 

[Explodersport]

nice. Is there anywhere else that I can get a new DPFE? I called napa and advance and they all thought I was stupid. I also asked for a EGR valve pressure feedback sensor and napa thought they might have one, but he didnt know if thats the right sensor I wanted. I found one on e-bay for like $60 dunno if this is worth it or not...

 

[spindlecone]

nice. Is there anywhere else that I can get a new DPFE? I called napa and advance and they all thought I was stupid. I also asked for a EGR valve pressure feedback sensor and napa thought they might have one, but he didnt know if thats the right sensor I wanted. I found one on e-bay for like $60 dunno if this is worth it or not...

Well if your DPFE system is history, you need a new one, are 40 bucks at peps or AZ, 70 from ford

 

[Explodersport]

alright, I will check the pep boys near my house. Thanks.

 

[Explodersport]

no one seems to have it except for napa for $63?!

 

[KaiserM715]

Update:

Codes are back!! They came back last week. I went to Autozone and had the codes run, same codes. I asked the guy to erase them and got a big speech about "against the law, $10k fine, certified mechanic, blah, blah, blah....". As it was indicating both banks are lean, I thought it might be the MAF. Yesterday I disconnected the battery, cleaned the MAF with MAF cleaner, reconnected the battery. Today, when I got home from work, I noticed the CEL is on again. Any thoughts?

 

[NHale623]

Are you sure the codes are the same ones you erased yesterday?

If you are, then I'd start looking for a vacuum leak.

 

[KaiserM715]

I have not been able to get the codes scanned again, yet, but I will bet that they are the same. If it is a vacuum leak, it must be pretty small as the drivabilty has not been affected at all.

 

[NHale623]

You need to get the codes. If they turn out to be the same codes you've been ignoring, then I'd start looking for a vacuum leak or fuel delivery problem.

I'd be looking at stuff like intake manifold o-rings, pcv valve, fuel filter, fuel pump, fuel pressure regulator, etc ...

There is either too much air, or too little fuel.

Or you could just reset the computer and see what happens. It's your truck.