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Thread: 02 f150 p0171

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    02 f150 p0171

    I have a 02 f150 54 truck and it seems to run fine but it throws the 0171 code sometimes and gets 10 miles per gallon I found a vacuum leak and fixed it but the long term fuel trim b1 still stays above 20 unless driving then it drops down ltft b2 stays a little bit high and the right side exhaust sounds like it's puffin

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    This could be quite a few things. Did you clear the code after fixing the leak and it still came back?

    Could be:
    A dirty MAF (especially if you use an oiled air filter)
    Bad PCV valve, or leaking PCV lines
    Exhaust leak as you said it might be
    Clogged fuel filter (if you haven't changed it within 30K miles do it, but that would likely affect both banks not just one)
    Dirty injectors so running some fuel system cleaner through the tank might be a good idea.

    Let us know what you find!

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    Quote Originally Posted by RhinoZ24 View Post
    This could be quite a few things. Did you clear the code after fixing the leak and it still came back? Could be: A dirty MAF (especially if you use an oiled air filter) Bad PCV valve, or leaking PCV lines Exhaust leak as you said it might be Clogged fuel filter (if you haven't changed it within 30K miles do it, but that would likely affect both banks not just one) Dirty injectors so running some fuel system cleaner through the tank might be a good idea. Let us know what you find!
    I had the same code. It was the pcv lines.

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    Doesn't mean it's the same for him young grasshopper. It's a pretty general code. Could be a bad O2 sensor too.

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    600 rpm.jpg1200 rpm.jpg2700 rpm.jpg

    tried to post these but phone wouldn't let me earlier when i made the post

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    Quote Originally Posted by RhinoZ24 View Post
    Doesn't mean it's the same for him young grasshopper. It's a pretty general code. Could be a bad O2 sensor too.
    well. Worth a look.

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    02 f150 pcv valve 2.jpg02 f150 pcv valve.jpg

    this is the one thats in my truck
    cheapest i found was 80$

  8. #8
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    Quote Originally Posted by Reconswrath View Post
    <img src="http://www.f150nation.com/attachment.php?attachmentid=10406"/><img src="http://www.f150nation.com/attachment.php?attachmentid=10407"/> this is the one thats in my truck cheapest i found was 80$
    yep mine is heated too. It was the connectors leaking. Mine is a 03. And since yours is a 02 it could very well be that. Look hard at all of it for oily substances on the hoses.

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    i replaced 2 of the elbows on th vacuum lines and drove it to work and back and it stayed under 10 on the LTFT 1 except for the startup leaving work

  10. #10
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    Quote Originally Posted by Reconswrath View Post
    I have a 02 f150 54 truck and it seems to run fine but it throws the 0171 code sometimes and gets 10 miles per gallon I found a vacuum leak and fixed it but the long term fuel trim b1 still stays above 20 unless driving then it drops down ltft b2 stays a little bit high and the right side exhaust sounds like it's puffin
    The puffing noise could be an exhaust leak upstream of the O2 sensor an exhaust pulse can pull in air the leak and create a false lean condition


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