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3 years of random misfire

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Old 10-02-2016, 02:05 PM
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and go get this truck to a snap-on motorvac. this is the best way to check for vacuum leaks. an engine builder i know (motorcycles and powersports/jetskis) uses it on every engine he works on. he gets surprised all the time. worth the $80 to have it done.
Old 10-02-2016, 02:06 PM
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Originally Posted by injectordyne
and go get this truck to a snap-on motorvac. this is the best way to check for vacuum leaks. an engine builder i know (motorcycles and powersports/jetskis) uses it on every engine he works on. he gets surprised all the time. worth the $80 to have it done.
Ive done smoke test no leaks whats so ever
Old 10-02-2016, 02:07 PM
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Originally Posted by Wolftrk99
Swapped engine, ecm, coils, wires, plugs, injectors, going to assume new intake gaskets when engine was replaced, no cats to be clogged, its starting to sound like a harness issue of some sort.... Could be a broken wire at the crank sensor, an issue with injector circuits or coild circuits or anything in between.... Have you by chance checked the map sensor and maf/baro sensor against what they are actually reading? Going to assume youve checked for vaccum leaks including the brake booster....
Yeah all checked
Old 10-02-2016, 02:11 PM
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Sounds like a harness.... I know at this point we are probbaly starting to sound like we are beating a dead horse, but you either have some sort of vaccum leak or a harness issue whether its a ground issue or whatever but you have eliminated all lther possiblities.. Time to look into a new harness!!!
Old 10-02-2016, 02:15 PM
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Originally Posted by Wolftrk99
Sounds like a harness.... I know at this point we are probbaly starting to sound like we are beating a dead horse, but you either have some sort of vaccum leak or a harness issue whether its a ground issue or whatever but you have eliminated all lther possiblities.. Time to look into a new harness!!!
i will replace the harness soon
But i wanted to know if some face this before
Old 10-02-2016, 02:36 PM
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Not to this extent i am sure...
Old 10-05-2016, 06:17 AM
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I am with them on harness, you replace damn near everything. Sorry for you trouble and headache man.
Old 10-05-2016, 06:19 AM
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What year truck, around 07-08 GM had bad harness step brother had a 08 GMC Sierra that had bad harness
Old 10-05-2016, 07:43 AM
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Have you ever had a crank relearn procedure performed ?
Old 10-05-2016, 10:45 AM
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Originally Posted by 06murder
What year truck, around 07-08 GM had bad harness step brother had a 08 GMC Sierra that had bad harness
Its a 2011 model , did the truck throw codes or like my truck no codes ?


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