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Miss firing


Swimmer8366

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Idle, and at cold temperatures, tells me there's probably an intake manifold leak.

 

  • High vacuum makes leaks more apparent (idle = high vacuum)
  • Cold temperatures make leaks more apparent (cold temps contract metal & plastic - any leaks become larger)
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Ended up doing intake gaskets injectors plugs wires and a fuel pump. Still misfire. Pulled driver side valve cover to check valve springs. Found

 

1ac33e7b1822f165bdae93a1fd791b67.jpg

 

Sent from my Z981 using Tapatalk

Idle, and at cold temperatures, tells me there's probably an intake manifold leak.

 

  • High vacuum makes leaks more apparent (idle = high vacuum)
  • Cold temperatures make leaks more apparent (cold temps contract metal & plastic - any leaks become larger)
Ended up doing intake gaskets injectors plugs wires and a fuel pump. Still misfire. Pulled driver side valve cover to check valve springs. Found

 

1ac33e7b1822f165bdae93a1fd791b67.jpg

 

Sent from my Z981 using Tapatalk

 

Sent from my Z981 using Tapatalk

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Cylinder 2 and 7 miss fire causing random miss code. Am I looking at an intake gasket leak?

 

Sent from my Z981 using Tapatalk

 

Good Evening Swimmer8366,

 

We are sorry to learn of the recent concerns you have been experiencing. We see that you are seeking the input of other forum members, so we would like to offer our assistance as well. Our team would be more than happy to look into your situation on our end. If this is something of interest, please send us over a private message so that we may continue with this process. Thank you and please enjoy the rest of your weekend.

 

Philip J.

GM Customer Care

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Just look at your freeze frame data - see what temperature the engine was at when the code set, and what the fuel trims are while it's running. If the code set on a cold engine, and your fuel trims are +10 or higher, and get better as it warms up, it's more than likely an intake gasket. If the trims are going negative, and the misfire is the same hot or cold, there's a good chance it's ignition related. Once all that is ruled out, then proceed with a compression and leak down test.

 

All you need is a spray bottle of water to spray along the mating surface of the head and intake - listen to the engine and watch the trims as you spray. Sometimes you'll even hear the water being sucked in too.

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Haven't really been able to get into it happened this morning way to work been at both jobs all day. I'm thinking it's an intake gasket because it is happening at cold but than again it continues the same through heat up and driving even back fires at times

 

Sent from my Z981 using Tapatalk

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Finally got to check the truck out for this miss fire problem. I decided to unplug my mass air flow sensor and run the truck. Once unplugged there are no more miss fires.

 

Sent from my Z981 using Tapatalk

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