P0301 code

CJ3

MEMBER
2008 CHEVROLET SUBURBAN
5.3L
V8
4WD
AUTOMATIC
145,000 MILES

The check engine light and stabilizer track light flash and then stay on. The OBD tool calls up code P0301. I have changed all 8 plugs and wires. Code still on, changed the coil for cylinder 1 and code still there. Changed the fuel injector for cylinder 1, code still active and both lights are still on. What else can I check?

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

If you only have a cylinder 1 misfire then we need to assume the basics that affect the other cylinders like air and fuel are okay for now. We may have to come back to them but since you have replaced the injector, plug, and coil, the most important thing to check is the compression at this point. Here are some guides that will help with this:

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

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

Once we know what the compression is on the cylinders on that bank we will have a better idea if this is the issue but this is the next step that we need to take. Thanks

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