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  1. #11

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    It's possible I suppose. Put a spark tester on the coil and check that.
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  2. #12

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    Haven't picked up the truck yet, but after O2 sensors were replaced emission metrics went down, but still didn't pass.
    Replaced plugs and wires, misfire is gone, but still didn't pass emissions.
    The mechanic recommended I just change to truck plates (gross weight over 10K), and emissions test won't be a problem anymore (not required). I've read about potential causes of high hydrocarbon (he said "high HC") and I guess will need to observe from driving experience (e.g. lack of power, or poor MPG), to try to aid if further fixing is necessary.

  3. #13

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    Truck appears to drive fine now. It doesn't have the occasional jitters anymore, however I do think it's somewhat weak in low RPMs.

    However, given that my other car is a mustang, and I've never driven a truck, I may just have high expectations on the performance truck, even though it does have a 5.7 engine.

    While I will probably follow the mechanic's advice and get truck plates, I am still worried about the high HC, as all readings I have done say it's unburned fuel, which means I'll be likely wasting money every time I drive it (or idle it, as below indicates)

    I do want to look at all options before I proceed with any further fixings.

    Here are the readings:

    HC ppm (limit 125)
    first reading: 212
    after o2 sensors replaced 157
    last reading 185

    HC @ 2500RPM (limit 125)
    first: 8
    second: 16
    third: 16

    so it appears it's not burning all fuel on idle only.

    Catalytic Converter and Gas Cap Pressure tests passed. I am not sure what they test with the CAT thou.

    BTW, mechanic says the computer is clean.
    He mentioned that the cylinders could be worn out.. but I don't see how that wouldn't be an issue at higher RPMs
    Last edited by NetComrade; 04-20-2012 at 02:07 PM.

  4. #14

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    Took the truck for a 50mile drive today of mixed highway/hilly/town driving. Drives much better.

    Then took it to an auto parts store, where I took a computer reading.

    Besides "speed signal missing" (c0226 and c0222), and a pair of potential electrical problems (c0281, stop lamp switch, and c0252 electonic brake controle module), everything seems OK.

    May attempt to do another emissions test.

    BTW, here, in VA, apparently only licensed emissions technician and centers can fix this stuff for you.

  5. #15

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    well, the injection cleaner didn't help.. didn't pass.
    i still feel there is something wrong (and emissions seem to prove it), but there are no engine codes.
    will look for a mechanic that can identify the issue instead of just swapping all the parts.
    i may attempt cleaning the MAF and EGR myself, as it seemed simple enough.
    not sure if I am capable of doing vacuum tests, but it is less logical to me that the vacuum problem would only cause the engine to run rich at low RPM.

  6. #16

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    I am a fan of the MAF sensor cleaning.


    I've discovered that it has a K&N filter, which can cause a dirty MAF sensor if improperly used.


    The idea of K&N filter doesn't appeal to me, even after reading all the "rave" reviews.

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