Random misfire and code p0300

1997 OLDSMOBILE BRAVADA
278,805 MILES • 4.3L • V6 • 4WD • AUTOMATIC
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MIKEY84
  • MEMBER
  • 1 POST
I just did a complete tune up and i keep getting gm p0300. i replaced the bank 1 sensor 3 o2 and that code disappeared. i cleaned the distributor cap on the inside and now the o2 sensor code is back as as is the p0300. how do i fix this?
Apr 23, 2019 at 8:43 AM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,246 POSTS
Welcome to 2CarPros.

A random misfire can be caused by many things. Such things as low fuel pressure, an engine vacuum leak, and so on can all contribute to the issue.

With that in mind, let me know what code you are getting for the sensor. That will help me determine what to check for. For example, is there a lean mixture at that sensor or a rich one? Is the low or high resistance to that sensor and so on.

I noted that you indicated cleaning the distributor cap. It could even have a crack in it. So check for that too. Last, take a look through this link. It discusses misfires, how to determine the cause, and how to fix one.

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

Let me know.

Take care,

Joe
Apr 23, 2019 at 1:43 PM
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