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  1. #1
    Bald Tire
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    Spark plug choices and idle stumble missfire

    Hey guys

    ac delco iridium at $9 each gap is .44
    or
    ngk iridium xl at $9 each gap is .43

    Question whats a better plug on a 07 hummer h3 with the 3.7 and why are both plugs show for the vehicle but different gaps.?


    Next heres a missfire issue

    not so perfect idle.Well its fine but if i give it gas then left off the gas the rpms drop and go very low then stumbles then evens out and runs fine but i had shop hook up to computer and there was a couple codes since last time.

    P0300
    B3152

    Also the live data shows cyc 3 missfire and when you press the gas and let go cyc 3 will give 3 or 4 missfires and cyc 2 and 5 show 1 but then dissapears and then all cyclinders show none and then after couple minutes cyc 3 will show again and after 10 minutes of running there was 16 on cyc 3 and 2 on 5.

    Could this be cause by dirty throttle body?

    I have changed battery terminals and enhuast manifold gasket and welded crack.
    spark plugs were changed a couple thousand kms ago due to random missfire. i checked and these are the plugs that were used 12625058 ACDelco Iridium Spark

    Any ideas?
    07 hummer h3 with the 3.7
    Last edited by blazed16; 04-15-2018 at 05:53 PM.

  2. #2
    Mud Terrain
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    I chose AcDelco.

    I'd replace the COP also.
    Clean maf & TB. Use the correct type of cleaner for each.

  3. #3
    Bald Tire
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    Quote Originally Posted by Happy Hummer View Post
    I chose AcDelco.

    I'd replace the COP also.
    Clean maf & TB. Use the correct type of cleaner for each.
    COP as replace all 5 coils?

    I have the maf and TB cleaner waiting just for some nice weather we still getting snow haha.

  4. #4
    Bogger
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    Swap coils around and see if the misfires shows up on the new cylinder. If the misfire moves then replace all the coils.
    2006 H3 Adventure & modified Rancho with SOA

  5. #5
    Bald Tire
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    3 2 and 5 all showed but 3 was worst. Im going to order a coil and switch with 3 and so on.

    Brand of coil motor products or ad delco ngk does it matter?

  6. #6
    Bald Tire
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    Quote Originally Posted by blazed16 View Post
    COP as replace all 5 coils?

    I have the maf and TB cleaner waiting just for some nice weather we still getting snow haha.
    3 2 and 5 all showed but 3 was worst. Im going to order a coil and switch with 3 and so on.

    Brand of coil motor products or ad delco ngk does it matter?

  7. #7
    El Diablo
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    Stay OEM and minimize any issues with aftermarket especially when troubleshooting an issue like this. You're not going to see a performance gain with different plugs or coils

    Sent from my SM-N950U using Tapatalk

  8. #8
    Bald Tire
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    Ok guys so i cleaned the maf and also pulled the throttle body and gave it a good cleaning.
    My crappy idle is alot better now.

    Hooked up for miss fire data and now cyl 5 had 16 misses and cyl 3 only had 3 in 4 minutes of idle. None on the other cylinders this time either.
    This was different from before as before cyl 3 was the one showing a bunch.

  9. #9
    Street Tire
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    How do your plugs look? How many miles are on the engine? And are you burning oil? Your plugs could be building up carbon deposits and fouling out from worn out valve seats dispensing oil into the combustion camber. Thats the problem I'm having with my Charger right now.
    I use mine.

  10. #10
    All Terrain
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    Stick with the stock plugs and from what I’ve read NEVER USE E3 plugs. All of the Hummer and Colorado forums say they will cause major issues...

  11. #11
    Bald Tire
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    Plugs look ok only about 8000km on them now and there the acdelco iridium thats recommended. No burning oil either. and there is 200,000km on the motor so that is high but really maintained.

  12. #12
    Bald Tire
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    Quote Originally Posted by blazed16 View Post
    Ok guys so i cleaned the maf and also pulled the throttle body and gave it a good cleaning.
    My crappy idle is alot better now.

    Hooked up for miss fire data and now cyl 5 had 16 misses and cyl 3 only had 3 in 4 minutes of idle. None on the other cylinders this time either.
    This was different from before as before cyl 3 was the one showing a bunch.
    Quote Originally Posted by mjferencak View Post
    How do your plugs look? How many miles are on the engine? And are you burning oil? Your plugs could be building up carbon deposits and fouling out from worn out valve seats dispensing oil into the combustion camber. Thats the problem I'm having with my Charger right now.
    Plugs look ok only about 8000km on them now and there the acdelco iridium thats recommended. No burning oil either. and there is 200,000km on the motor so that is high but really maintained.

  13. #13
    Super Swamper
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    Try a set of coil paks. Way overdue at 200k.

  14. #14
    El Diablo
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    Quote Originally Posted by 4speedfunk View Post
    Try a set of coil paks. Way overdue at 200k.
    That's one of the few things that I have not had to replace. #knockonwood

    Sent from my SM-N950U using Tapatalk


 

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