Code P0300, misfire

Tiny
GARETHEBARE
  • MEMBER
  • 2006 NISSAN XTERRA
  • 4.0L
  • 6 CYL
  • 4WD
  • MANUAL
  • 208,000 MILES
Misfire at idle and up to about 2,000RPMs. The only code is p0300. First time it misfired when going up a long hill.
Wednesday, May 4th, 2022 AT 11:56 AM

1 Reply

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,644 POSTS
Since the misfire is random and not specific to one cylinder, chances are there is an issue with either a fuel pressure-related problem or even an engine vacuum leak.

If you have a live data scanner, let me know what the short-term fuel trims are. I can tell if it is a fuel mixture-related issue from that.

Also, check to make sure there are no vacuum leaks. Here is a link that explains how to locate and repair a leak:

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

If nothing is found and you can't get the short-term fuel trims, the next suggestion is to confirm the fuel pressure is within specification. Here is a link that explains how to check fuel pressure:

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

If you look at the attached pic, it provides the manufacturer's fuel pressure specifications.

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

Take care,

Joe

See pic below.

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Wednesday, May 4th, 2022 AT 8:56 PM

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