Code p300 random misfire

2003 CHEVROLET MONTE CARLO
140,000 MILES • 3.1L • 6 CYL • 2WD • AUTOMATIC
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SAMGREW
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  • 54 POSTS
Car surging with misfire.
Apr 11, 2018 at 3:19 PM
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ASEMASTER6371
  • CAR REPAIR CONTRIBUTOR
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good evening.

How old are the ignition components?

the most common cause for this code is low fuel pressure. do you have a tester to check the fuel pressure?

Roy
Apr 11, 2018 at 3:31 PM
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RENEE L
  • CAR REPAIR CONTRIBUTOR
  • 1,260 POSTS
Hello SAMGREW,

Thank you for visiting 2CarPros. Here is a link to an article from this site with step by step instructions and pictures explaining the process of checking the fuel system pressure, regulator and fuel pump in less than fifteen minutes:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

If you need further assistance please come back to the site we are always happy to help.

Kindest regards,

Renee
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Apr 11, 2018 at 5:05 PM
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SAMGREW
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Furl pressure is between 52 to 57 psi. Engine skips at idle and at high engine rpm engine surges.
Apr 12, 2018 at 12:27 PM
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ASEMASTER6371
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Okay, that reading is good.

Try disconnecting the EGR valve electrical connector and drive it and see if it continues.

Roy
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Apr 12, 2018 at 1:19 PM
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SAMGREW
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Disconnected EGR electrical connector. No change.
Apr 13, 2018 at 6:38 AM
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ASEMASTER6371
  • CAR REPAIR CONTRIBUTOR
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Okay not the EGR. I would also check the catalytic converter. An easy way to check is to remove one of the upstream O2 sensors and drive it and see if it changes. that will check for partial restriction in the converter.

Roy
Apr 13, 2018 at 7:17 AM