Another Lean Code

[13 Z]

So I got the infamous P0171 and P0174 codes saying banks 1 and 2 are both lean. I did some research on here and immediately checked the vacuum lines as prescribed by numerous members. :bash: No dice:bash: . I sprayed carb cleaner back there and got no response from the L. I then pulled the MAF just to make sure it was intact and not dirty. It looked clean enough to eat off of. I cleared the code, and I’m pretty sure it will return shortly. What should I look for now? Would a fuel filter cause this? Injectors? I’m stumped as to what this could be…any help would be appreciated.

 

[mikeb82992]

Change the fuel filter...see if its flowing freely...cut it open...Careful!...look at the media...I just burned up a fuel pump on another truck I have...got bad gas somewhere in KY...you do not want to be lean

 

[13 Z]

Ok, I'll try to get to that later. Any tips to make it go easier?

 

[mikeb82992]

Man...there is a lot of info in these forums...if you never changed a fuel filter before on a ford, get the tool that un hooks the spring on the fuel line...the filter is on the frame rail on the pax side...be sure to bleed the pressure off before you pull the filter lines loose or you might get a face full of fuel...make sure you got something to drain the fuel into...it is not a lot...but it doesnt take much for fumes to start a fire...not trying to scare you, after you do it once its a breeze...good luck wrenching...its part of owning a Lightning

 

[ChuteboxeL03]

If you do it while smokin a fattie, its seems to make it alot easier lol

 

[13 Z]

So...I put a new fuel filter on and the light came back. The old one was really hard to blow through, so I thought it was the cause. Nope. Should I look for a bad O2 sensor now? Fuel injectors? I'm lost at this point...


Could a ford dealer pinpoint it?

 

[Nvr_Spds]

You can also try cleaning the MAF just in case. You never know, something may be on it.

 

[pitstain]

do you have any mods done?

 

[13 Z]

do you have any mods done?

Nope, bone stock.

 

[BT2001SVT]

My truck threw the same code, I did the same test you did to see if any of the lines where breathing- nothing. Wound up at the dealership (extended warrantee) for 28 f**kin days. They ended up on the phone with the factory for days and tried everything from vaccum lines, MAF, even said at one point the my computer's processor had gone bad, so they changed that too; same code. In the end they said it was the intake manifold gasket, so they replaced it along with a few other gaskets and she's been fine ever since, except for 2 days after I got her back the EGR valve went bad. I'm gonna do the EGR delete this weekend since we don't have emmission laws anymore in Florida.

All this just happened last month. sometimes i think it was something stupid, like a vaccum line and the dealership was just trying to get paid for extra labor off the warrantee company, but that's just me looking for the worst in them; just pissed it took soo long.

Sorry for the long post, just had to vent- I hope you don't have the same issue and it all waroks out for you bro.

 

[fullboogie]

Still willing to bet you have a vacuum leak.

 

[RIDE THE]

With both banks reading lean it really sounds like a vacuum leak. It's possible that an O2 sensor might be bad but unless something is really F-ed up I can't see both sensors going bad at the same time.

 

[13 Z]

RE the Vacuum leak....how much carb cleaner do you have to spray back there in order to get the truck to suck it in? I spent about 20 minutes trying to find a leak, but I got no response from the L.

 

[RIDE THE]

Short, little 1 second bursts will be enough to raise the short term fuel trim. If spraying behind the SC on the lower PCV hose connection doesn't make any difference in the idle speed then spray everything else. Check it when it's dead cold. Sometimes heat can swell up a seal and the leak goes away.

Spray, listen for RPM change, wait, Spray, listen for RPM change. Over and over. A leak could be anywhere above the lower intake gaskets or any of the vac lines. Even check the connections behind the battery box by the firewall. Just don't spray to much on the SC or the Plenium. It will take off the exterior coating if you spray to much on.