Random misfires

2004 CHEVROLET TRAILBLAZER
118,000 MILES • 4.2L • 6 CYL • 4WD • AUTOMATIC
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GRIVICCIO
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Car runs rough, check engine flashes. Changed plugs and one coil (originally said number five misfire) now says random misfires.
Feb 28, 2019 at 12:28 PM
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ASEMASTER6371
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Good afternoon,

Was the 305 and 300 the only codes?

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

I would start by checking the fuel pressure. Low pressure will cause this issue.

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

Roy
Feb 28, 2019 at 12:45 PM