Engine misfire and code P0301

2003 NISSAN MAXIMA
126,000 MILES • 3.5L • 6 CYL • 2WD • AUTOMATIC
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MUSICSPEAKS0316
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So about a week or two ago I had a code P0301, I replaced the spark plug and coil pack and it ran perfectly. Then yesterday the engine started to misfire again and the same code pop back up for the same cylinder. I need help so identify the problem, and I don't have a lot of money to take it to a mechanic to find out. I'm wondering if it could be the coil pack or the spark plug that I just replaced because it was running just fine for 2 weeks. Or what else I can check to fix the problem?
Feb 20, 2021 at 2:22 PM
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JACOBANDNICKOLAS
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Hi,

It could be either or something totally different. Here is what I suggest to try: Switch the new coil with the coil from a different cylinder. See if the misfire changes cylinders. If it does, then the coil is bad and should be under warranty.

If you want to check it for spark, here is a link explaining how to do it:

https://www.2carpros.com/articles/how-to-test-an-ignition-system

When the coil is off, remove the spark plug and see if it looks normal.

Let me know what you find or if you have other questions.

Take care and God Bless,

Joe
Feb 20, 2021 at 9:41 PM
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MUSICSPEAKS0316
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Unfortunately, for my car to access the number one cylinder you have to pretty much completely remove the intake. So that means I would have to remove the intake swap the plug or coil and then put back on the intake test it and then remove it again if it's not that.
Feb 21, 2021 at 10:41 AM
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JACOBANDNICKOLAS
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Hi,

That slipped my mind. Ugh! I have no idea why they design things like this. However, the only thing we can do is check it. Based on the mileage, I don't think it would be a compression issue. If there was a vacuum leak, I would suspect other cylinders would be affected as well. It could be a fuel injector issue. Here is a link showing how that is checked:

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

Just for curiosity, where did you get the plugs and new coils? Was it online?

Let me know.

Joe

Feb 21, 2021 at 6:59 PM
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MUSICSPEAKS0316
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To be completely honest I was kind of stranded and just bought a $70.00 coil pack and I bought the cheapest spark plug that I can find so that might be the issue. It's a strange to me how I can replace those two things and it be fine then all the sudden stop working. again it makes me believe it's one of those two objects that I replaced.
Feb 21, 2021 at 7:36 PM
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JACOBANDNICKOLAS
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It is very possible. I asked about getting something online because I have seen a lot of faulty parts. I have a feeling you are correct.

Let me know if I can help in any way.

Take care,

Joe
Feb 21, 2021 at 7:47 PM