Misfire dilemma?

Tiny
SHANE TAYLOR
  • MEMBER
  • 2010 FORD FUSION
  • 3.0L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 180,000 MILES
Car began running rough and check engine light came on, ran diadnostic and said cylinder 1 misfire coil a primary/secondary, change coil, swapped plug with diff cyl to save money plus they arent very old, however still misfiring, I even swapped coils with another cyl and still have trouble with same cyl, runs ok when in motion but idles rough. Tried unplugging coil while car runnin but no change, check all connections and all show same voltage. At a loss for further diagnosis?Could be power control module mabye, your thoughts
Shane and greg
Saturday, August 2nd, 2025 AT 9:51 PM

8 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Yes, I would check the compression first, also what does the old spark plug look like? Can you upload an image? You may have a bad fuel injector, this is why we need to look at the spark plug, here are two guides to help us fix the problem or at least find out what is going on.

https://www.2carpros.com/articles/how-to-test-engine-compression

and

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

Please upload pictures or videos in your response
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Sunday, August 3rd, 2025 AT 12:23 PM
Tiny
SHANE TAYLOR
  • MEMBER
  • 22 POSTS
We were able to plu a long extension on injector and it sounded like the other injectors. Heres a pic of the plug, I will have results from compression test soon.
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Monday, August 4th, 2025 AT 3:40 PM
Tiny
KEN L
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Yep, the spark plug looks normal, I would do the compression test, thanks for the images they help. I would still swap a new spark plug in there just in case.
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Tuesday, August 5th, 2025 AT 8:18 AM
Tiny
SHANE TAYLOR
  • MEMBER
  • 22 POSTS
My compression tester was not working properly however we did test the ohms that each injector was showing and turns out that injector was showing way more ohms than the others leading us to belive its a faulty injector. We will be replacing soon and will post a result. Looks like you were correct in ur original assesment.
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Tuesday, August 5th, 2025 AT 11:03 AM
Tiny
KEN L
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  • 54,137 POSTS
Yep, that will do it. Glad it looks like you found the problem. But we don't say its "fixed" until it goes down the road for two weeks! :) Please let me know.
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Tuesday, August 5th, 2025 AT 12:30 PM
Tiny
SHANE TAYLOR
  • MEMBER
  • 22 POSTS
Yes sir will do, once again thanks to 2carpros and to Mf Ken for putting us on thd right track. Will follow up with a final report soon
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Tuesday, August 5th, 2025 AT 12:32 PM
Tiny
SHANE TAYLOR
  • MEMBER
  • 22 POSTS
MR KEN, sorry for typo
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Tuesday, August 5th, 2025 AT 12:32 PM
Tiny
KEN L
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  • 54,137 POSTS
No worries!
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Tuesday, August 5th, 2025 AT 12:51 PM

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