Cylinder misfire and engine misfire, how do I fix this?

2005 SATURN VUE
301,072 MILES • 3.5L • 6 CYL • AUTOMATIC
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MENDOZA85
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Engine light blinking so I put the ob2 reader and codes that popped up was cylinder 5 misfire/engine misfire/ cylinder 6 misfire. What could be the problem or how do I fix it? someone else put new spark plugs and coil packs, so what's going on? What should I do, I'm lost?
Jun 14, 2024 at 1:33 PM
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JACOBANDNICKOLAS
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Hi,

If the new plugs and coil packs didn't help, it could be a couple of things. For example, there could be a fuel injector issue. Also, with that many miles, it could be a head gasket or simply low compression in those cylinders.

I suspect you had P0305 and P0306 codes. Were there any other codes?

Also, since cylinders 5 and 6 are next to each other, the first thing I would be checking is for engine compression in those cylinders. A faulty head gasket can leak between the two. See pic below for cylinder orientation.

Here is a link that explains how to check compression. You will need a compression gauge, but most parts stores will lend one to you.

https://www.2carpros.com/articles/how-to-test-engine-compression

Let me know if that is something you are comfortable performing.

Take care,

Joe

See pic below.
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Jun 14, 2024 at 7:43 PM
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JACOBANDNICKOLAS
  • CAR REPAIR CONTRIBUTOR
  • 110,190 POSTS
Hi:

If the new plugs and coil packs didn't help, it could be a couple of things. For example, there could be a fuel injector issue. Also, with that many miles, it could be a head gasket or simply low compression in those cylinders.

I suspect you had P0305 and P0306 codes. Were there any other codes?

Also, since cylinders 5 and 6 are next to each other, the first thing I would be checking is for engine compression in those cylinders. A faulty head gasket can leak between the two. See pic below for cylinder orientation.

Here is a link that explains how to check compression. You will need a compression gauge, but most parts stores will lend one to you.

https://www.2carpros.com/articles/how-to-test-engine-compression

Let me know if that is something you are comfortable performing.

Take care,

Joe

See pic below
Jun 14, 2024 at 7:43 PM