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Thread: Bad gaskets or something I did?

  1. #1
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    Bad gaskets or something I did?

    So earlier in the month I put new knock sensors in the truck, and decided to throw some new intake gaskets on while I was in there. Fast forward about three weeks/3-400 or so miles and my check engine light comes on. P0174 Bank 2 system to lean. I hosed the intake with some brakleen and couldn't find anything as far as a noticeable leak. The other odd thing that I noticed is that since the engine light came on, the truck has been acting odd, as in every few times I stop, it acts like it has a big vacuum leak, idles extremely choppy and rough. However it doesn't do this all the time...just every few stops. Anyone have any ideas what's going on?
    Always buying things I dont need to impress people I dont know

  2. #2
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    What brand intake gaskets did you use?

    I have seen a couple of intakes that were warped from not being bolted down in the correct sequence.
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  3. #3
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    I used the Felpro set, and I made sure to go in the sequence and torque them down in two steps as listed.
    Always buying things I dont need to impress people I dont know

  4. #4
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    I've read a service bulletin about the seal in the brake master cylinder leaking causing issues. I'm about to change mine out too. It can't be too expensive.
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709

  5. #5
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    Quote Originally Posted by RedHeartbeat View Post
    I've read a service bulletin about the seal in the brake master cylinder leaking causing issues. I'm about to change mine out too. It can't be too expensive.
    That would make sense, because it usually is when Im in gear and on the brakes that it is worst. my only question is why would it only cause bank 2 to run lean?
    Always buying things I dont need to impress people I dont know

  6. #6
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    usually when I find one bank lean it is most often due to 02 sensors on the way out. You could have a vacuum leak. I'm not sure which cylinder is closest to the brake booster but if the booster is leaking, that cylinder would run lean.
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709

  7. #7
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    It shouldn't be the o2 sensors, they are next to new from earlier this fall. Im gonna assume a vacuum leak because there were also a few knock sensor codes that popped up, though they haven't come back after clearing it out the other day. So I can only guess it ran lean enough to trigger them on the highway. I just haven't been able to find any obvious leaks as of yet.
    Always buying things I dont need to impress people I dont know

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