Cylinder six misfire

2009 CHEVROLET SILVERADO
180,000 MILES • 5.3L • V8 • 4WD • AUTOMATIC
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PULLEY
  • MEMBER
  • 1 POST
The truck listed above is an z71, it gave me code for cylinder six misfire, but code went away, and it still has a miss at idle but can give it heck and let it idle doesn't miss for a little bit, then comes back.
May 11, 2022 at 7:24 AM
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KASEKENNY
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 18,907 POSTS
We need to start with making sure this is a misfire and not something else like a vacuum leak that will make it feel like it is misfiring.

Here is a video that will help with intermittent misfires to get us started:

https://youtu.be/UKB-ytgbnzU

The way to prove this out is we need to watch the o2 sensor data and find out if this is showing a lean or rich condition when you are feeling this misfire.

If there is no change in the o2 sensor data but you can feel the misfire, then the sensors may be the issue.

Please see the chart below that will help with fuel trim/o2 sensor info.

Lastly, we need to check for a vacuum leak which will cause this as well.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let's start with this info and go from there. Thanks
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May 11, 2022 at 6:01 PM
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