02 suburban 5.3 lopes on cold start

Discussion in 'Engine & Drivetrain' started by NvrMnd85, Aug 5, 2018.

  1. NvrMnd85

    NvrMnd85 TYF Newbie

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    Ok if i don't drive the truck for a day or 2 itll lope on cold start for a few, sounds like it has a nice cam in it. I run it on e85 and im sure its part of that. Just curious what it is. Im assuming its the computer being grumpy. And as long as its not hirtihu anything ill just leave it.
     
  2. Doubeleive

    Doubeleive Elite Member Supporting Member

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    video?
     
  3. Scottydoggs

    Scottydoggs Full Access Member

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    id guess you have a huge vacuum leak. you can check the long term fuel trims, if they are pos +16 its a vac leak for sure.
     
  4. NvrMnd85

    NvrMnd85 TYF Newbie

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    It only does it on cold start up after its been sitting for a day or two, which doesn't happen much. It only does it on e85 also and ive only noticed it in the middle of a hot day.


    Ill try to get video next time it does it.

    I figure its something in the tuning caise it smooths out and runs great and it wont do it again on cold start up till the next time i don't drive it for a day.
     
  5. SnowDrifter

    SnowDrifter Full Access Member

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    How cold are we talking?

    e85 isn't exactly known for its cold weather performance
     
  6. NvrMnd85

    NvrMnd85 TYF Newbie

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    This was yesterday when it was 90°f out. Engine was at cold temp when started. It does do it nore commonly in winter but its nowhere near are harsh a lope as it did yesterday.

    I think its just the computer being slow on adjusting timing and fuel trims. Just didn't know if anyone had had this before.
     

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