Results 1 to 5 of 5

Thread: trying to correct tune. freeway cruising makes backfire/misfire popping sound

  1. #1
    Tuner in Training
    Join Date
    Aug 2023
    Posts
    15

    trying to correct tune. freeway cruising makes backfire/misfire popping sound

    hello everyone.

    i am looking for guidance with my tune. specifically trying to correct a flashing engine light, not sure if it is a misfire, or backfire but while cruising on freeway, it makes a popping noise that has a loss of power feeling. also, slight grinding feeling when accelerating from a stop.

    truck in question is 2009 gmc sierra 1500, 4x4 5.3 with truck norris nsr cam, afm/dod delete (plugs installed, and all 16 lifters are ls7)
    ecu was bench tuned.

    since cam install, had problems with loss of vacuum. to the point the truck would stall out, or go into limp mode.
    had a new ecu bench tuned, it solved the staling out problem, but vac problem is still ongoing.

    installed new : break booster, oil pressure sensor, maf sensor, spark plugs, ignition coils and wires

    now i have purchased hp tuners to log data myself in an attempt to help solve my issues.

    any guidance/ help is appreciated.
    Attached Files Attached Files

  2. #2
    Senior Tuner
    Join Date
    Nov 2017
    Posts
    1,464
    Post in gen4 GM v8 section to get more help. Include the tune in addition to the log.

  3. #3
    Tuning Addict 5FDP's Avatar
    Join Date
    May 2012
    Location
    Rogers, MN
    Posts
    13,565
    Yeah it needs a lot of work just looking at the log, pretty rich in a ton of spots.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  4. #4
    Tuner in Training
    Join Date
    Aug 2023
    Posts
    15
    since i had it bench tuned by pros,
    you think they gave me a shit tune,
    or would the fact its rich in a ton of spots indicate something like fuel injector stuck open?

  5. #5
    Tuner in Training
    Join Date
    Aug 2023
    Posts
    15
    will do , thank you