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Thread: P0171 and P0174 lean codes

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    Former Owner of 03 #8186
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    P0171 and P0174 lean codes

    Both codes show lean on bank 1 and 2, I have sprayed all vaccum lines with carb cleaner and idle didnt change a single digit. I can unplug the MAF sensor while its running and it wont change the idle any either, but when I plug it back up it will idle down for a second as if the AC kicked on. Also the AC will only blow out of the panel if I set the AUTOMATIC temp above 78, which tells me there may a leak in the HVAC system, any ideas of where to look? I have cleaned the MAF with CRC cleaner but no success. WHen taking off from stop the engine almost sounds like it has exhaust leaks spitting from the collector gasket but all of that is tight, could I be hearing detonation?? IT wont do it under WOT. PLEASE CONTRIBUTE ALL IDEAS!! Thanks!!

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    Former Owner of 03 #8186
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    anybody?

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    yes please someone... my HD is suffering from this code... someone please help

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    For your AC issue you could have a vacum leak on your ECU itself. The o-rings have a tendency to wear out and leak. It is a simple fix and only costs you a couple bucks.

    http://www.nhtoc.com/vbforum/how-art...oblem-but.html

    The lean codes could be as simple as a loose connector. Make sure you check the little connector on the bottom of your air intake tube. Alot of people miss that one when they re-install the MAF.
    Last edited by 2manytrucks; 05-31-2011 at 11:32 PM.

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    Just curious have you cleaned your IC recently? there is a tube that runs from the back of your lower intake to the passanger side ...this has been a know place to have a vac leak....your ac and vc leak are probably 2 differnet things. as stated above the o ring trick normally fixes AC problems...Do you know anyone that you mightbe able to swap MAF with?

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    Had the same problem, I unhooked my MAF and the hope into my intake and reinstalled them. Havent had a code light yet!

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    Former Owner of 03 #8186
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    UPDATE! Problem was the vacuum line on the lower intake, I believe it tees off from the PCV line and runs down, replaced and codes went away, runs great!

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    i got mine to go away for about 3.5 weeks by cleaning the MAF. then i ran a little bit of regular gas one day cause i was broke... and about an hour later it came on ... dont know if that was the reason but it came back on.

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    so i cleaned the MAF again and the damn thing is back!!!!!!!!!!!!!!! Can some one please help !! i have a K&N system and ive heard it could be the oil from the filter... but i want to know if i need a new cone, new intake, new maf or is there something else that could be wrong with my truck? I mean is there sometthing else this bank 1 runnin lean code could mean?

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    HiTech Redneck
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    I think the most common cause is the elbow for the lower pcv hose.
    It is at the very bottom of the lower intake. I just fixed mine after chasing it since December.
    First off, it's a lean code, which means that when the ses light is on, the fuel trims are maxed out rich. Not good!@ Neither is lean.
    Because of age and engine heat, the thing just basically rots.
    You almost have to pull the sc to replace it, unless you have tiny hands and are a contorsionist plus being double jointed.
    Did mine in about 3 - 4 hours counting painting the intake and sc.
    You can't see it at all, just feel it when the sc is off.
    Here's a shot of the old (broken in two) and the new elbow.
    The entire hoses, junctions etc are available from ford.com
    It's a cheap fix - mostly your time to pull & reinstall the sc.
    Attached Images Attached Images

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    wow sounds like a pain in the ***!!! anyway of being able to check without pulling all that off? cause that would suck pullin all that stuff off and end up not being the problem

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    Quote Originally Posted by 2003f150harley View Post
    wow sounds like a pain in the ***!!! anyway of being able to check without pulling all that off? cause that would suck pullin all that stuff off and end up not being the problem
    Find someone with little hands lol...just delete the pcv system like I did...problem solved!

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    HiTech Redneck
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    Her is how I confirmed mine - watch the fuel trims while spraying carb cleaner straight down where the elbow is located. If the P0171 is on, the fuel trims will be maxed. When the carb cleaner hits the vacuum leak they will drop back down momentarily.
    As you can see, when I reached down to pull the old elbow off it broke in two.
    I wish I had done mine a lot sooner as a leak like that is nbot good!

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    Quote Originally Posted by 2003f150harley View Post
    wow sounds like a pain in the ***!!! anyway of being able to check without pulling all that off? cause that would suck pullin all that stuff off and end up not being the problem
    Get a fog machine and fog in after your MAF....motor off....make sure you open TB and look for where the smoke exits.

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    Quote Originally Posted by UserName View Post
    UPDATE! Problem was the vacuum line on the lower intake, I believe it tees off from the PCV line and runs down, replaced and codes went away, runs great!
    I had a similar problem with mine as well. The tube that runs from the lower intake to the passenger side - the rubber elbow at the top of the tube was tired and stretched so the plastic tube was falling out of it. Replaced the part (tube and elbow are one part) and performance, especially during acceleration improved noticeably.

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