gmc missfire problem

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ttst527
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Joined: Fri Nov 15, 2013 5:42 pm

gmc missfire problem

Unread post by ttst527 » Fri Nov 15, 2013 6:03 pm

i have a 06 gmc envoy with a random missfire code. i only have problems when the temperature is cold outside when starting. once motor reaches 200 degrees it will run just fine. ive replaced spark plugs, had a bg fuel injector cleaning done on it. now i'm lost.

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carriedi
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Joined: Wed Apr 10, 2013 12:42 pm

Re: gmc missfire problem

Unread post by carriedi » Sat Nov 16, 2013 4:09 pm

when the engine is cold it is harder for the spark to jump across the plug. It will look for an easier way to ground if it can find one. When was the last time plugs and wires were replaced? it could be that they are starting to break down. Just food for thought.

an intake leak is also very common for these motors. when the parts are cold the leak may be more evident. as the engine warms up and parts expand from the heat and the computer takes over the fuel mixture the leak may not be as noticeable.
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ttst527
Posts: 3
Joined: Fri Nov 15, 2013 5:42 pm

Re: gmc missfire problem

Unread post by ttst527 » Sat Nov 16, 2013 7:48 pm

the plugs are new. i'll check for air leaks. Thanks

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carriedi
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Re: gmc missfire problem

Unread post by carriedi » Sun Nov 17, 2013 5:00 am

I have also had it where the injectors are a little dirty and will cause a very slight miss that you might not even feel but the computer will register a random misfire code. In injector cleaning like a motor vac can clear this up
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ttst527
Posts: 3
Joined: Fri Nov 15, 2013 5:42 pm

Re: gmc missfire problem

Unread post by ttst527 » Fri Dec 27, 2013 7:21 pm

update; the intake manifold bolts will loosen up over time. some were ready to fall out. i just snugged the bolts back up and it fixed the problem

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carriedi
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Re: gmc missfire problem

Unread post by carriedi » Sat Dec 28, 2013 2:59 am

Congrats,
thanks for letting us know what it was
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