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Check Engine Light on with codes P0300, P0302 and P0303?

Tiny
OREO101
  • MEMBER
  • 2005 FORD EXPEDITION
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
Hi,

My car is due for inspection in PA.
I get codes P0300, P0302 and P0303.
Showing misfires.
I will replace spark plugs and coil packs for #2 and #3 cylinders.
I did the other plugs and coil packs for other cylinders.
Luckily the plugs have been replaced before, so the plugs are 1 piece and not the dreaded original 2-piece that had possibility of breaking off in cylinder.
Could there be other causes for these CEL codes?

Thanks!
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Sunday, March 24th, 2024 AT 8:08 PM

3 Replies

Tiny
BORIS K
  • MECHANIC
  • 762 POSTS
Hello,

The most common causes for misfire on these 5.4 3V engines are spark plugs and coils.

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

A few other causes can be injector malfunction and intake air leaks.

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

https://www.2carpros.com/articles/engine-misfires-or-runs-rough
and
https://www.2carpros.com/articles/automotive-engine-misfire-code-p0300-causes-and-solutions

Hope this helps.

Cheers, Boris
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Monday, March 25th, 2024 AT 5:35 AM
Tiny
OREO101
  • MEMBER
  • 81 POSTS
Yes, it does!
Thanks!
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Monday, March 25th, 2024 AT 11:36 AM
Tiny
BORIS K
  • MECHANIC
  • 762 POSTS
Thank you for using 2CarPros.

Please let us know if we can assist with anything else car related.

Cheers, Boris
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Tuesday, March 26th, 2024 AT 6:52 AM

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