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  1. #1
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    Default 2000 GTP Misfire

    Okay so I just got a new GTP the mods are 3.4 pulley, pacesetter headers, 3" inch zzp exhaust, wizaird intake system, zzp tuned. I have a aeroforce scanner and i'm getting a misfire on cylinder #4 at idle. Now it goes away if you turn on A/C or accelerate. My scan gauge does not read any misfires under accelerating. I'm wondering if anyone would know why i'm getting these misfire?

  2. #2
    Turbo is the way to go. Fivefingerdeathpunch's Avatar
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    Default Re: 2000 GTP Misfire

    Swap plugs around, see if it follows.

    SMGPFC Member #1

  3. #3
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    Default Re: 2000 GTP Misfire

    Same with injectors.

    Check vacuum lines and coil packs, too.
    1999 Chevrolet Silverado K1500 Classic Z71 - Intake/Gibson Exhaust - The Daily
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  4. #4
    GTP Level Member buickman104's Avatar
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    Default Re: 2000 GTP Misfire

    Are you getting any codes or pending check engine lights?
    2000 Bronze Metallic GTP
    Power :Gen V, 3.6 pulley, 3 inch down pipe, Power log, FWI,and DHP Power Tuner,
    Handling: Vogtland Springs, GMPP sway bars, STBS, 18" Konig backbone, CTS-V Front brakes and GXP rear brakes

  5. #5
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    Default Re: 2000 GTP Misfire

    No I'm not getting any check engine lights. Coils are new along with plugs. They are autolite 104s. I got injectors from zzp just stock but they were tested good before I got them

  6. #6
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    Default Re: 2000 GTP Misfire

    Also forgot to mention new 10.5mm plug wires from zzp. New idler pulley, water pump, crank sensor, new lim gaskets.

  7. #7
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    Default Re: 2000 GTP Misfire

    what vacum lines should be checked

    Quote Originally Posted by blueguy91 View Post
    Same with injectors.

    Check vacuum lines and coil packs, too.

  8. #8
    Killa Bee Scottydoggs's Avatar
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    Default Re: 2000 GTP Misfire

    did this miss come after the plug change? if so you likely cracked the spark plug. swap it with the one next to it, see if the miss moves.

    you might just see a black line in the plug too, then you know its cracked.

    or you got a chipped piston.

    98 Buick Regal GS, F body brakes, Caddy STS wheels, tinted tails L36 bottom end, lightly ported heads, 1.95 roller rockers, headers, 2.8, FSIC, 42 lb injectors, a BrandonHall rebuilt trans, DHP tuned and AEM water/Meth injection https://goo.gl/gpV5kW

  9. #9
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    Default Re: 2000 GTP Misfire

    Air/Fuel/Spark...

    with misfire, swap plug (check gap too), wire, coil pack, then injector. Do this to see if the misfire follows, if so, you've found your problem. If not, then compression test, problem could be heads (valve) or worse, as Scotty says, a piston with a hole in it.

    I'm going to bet coil pack
    Overkill BBC Cam, YT 1.8 RR's, Rhodes Lifters, STGII Heads, GenV, Pacesetters, 3" Exh to Tips, TEP Trans. N*, ID 75# injectors/E85 coming soon

  10. #10
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    Default Re: 2000 GTP Misfire

    What should a compression test run with a motor that has 212 on it?

  11. #11
    Killa Bee Scottydoggs's Avatar
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    Default Re: 2000 GTP Misfire

    how about some back story, why i asked the questions i asked.

    98 Buick Regal GS, F body brakes, Caddy STS wheels, tinted tails L36 bottom end, lightly ported heads, 1.95 roller rockers, headers, 2.8, FSIC, 42 lb injectors, a BrandonHall rebuilt trans, DHP tuned and AEM water/Meth injection https://goo.gl/gpV5kW

  12. #12
    Turbo is the way to go. Fivefingerdeathpunch's Avatar
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    Default Re: 2000 GTP Misfire

    It might vary some but 150-165ish give you take some.

    So long as one cylinder is way low compared to the others, like if all are at 160 but cylinder 2 was at like 130 then you may have an issue.

    SMGPFC Member #1

  13. #13
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    Default Re: 2000 GTP Misfire

    Sorry scotty.. the car was my dad's he had it for 10 years. He meticulously took care of his vehicle(s). Each cylinder was reading 150 - 160.. also even after plug changes it's been doing it for the last year or so he hasn't figured it out.. it's a weird misfire..

  14. #14
    GTP Level Member buickman104's Avatar
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    Default Re: 2000 GTP Misfire

    I had constant misfires on cylinder 4 for about a year until I started getting other cylinder misfires and it turned out to be a crank sensor.
    2000 Bronze Metallic GTP
    Power :Gen V, 3.6 pulley, 3 inch down pipe, Power log, FWI,and DHP Power Tuner,
    Handling: Vogtland Springs, GMPP sway bars, STBS, 18" Konig backbone, CTS-V Front brakes and GXP rear brakes

  15. #15
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    Default Re: 2000 GTP Misfire

    Quote Originally Posted by buickman104 View Post
    I had constant misfires on cylinder 4 for about a year until I started getting other cylinder misfires and it turned out to be a crank sensor.
    Could the problem also be the fuel pressure regulator??

    Sent from my LGMS550 using Tapatalk

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