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Misfire Codes

Jim Bronson

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Has anyone had success having a dealer fix the cylinder 8 and random misfire codes? I don't notice any other symptoms, but I had the check engine light come on and then I reset and it came on again in a few days. So something is wrong.
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Shifting_Gears

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I am get a P0300 and P0308. Random misfire and cyl 8.

I am pretty sure it’s a failure of the intake manifold runner plates. What year is your car? Seems to be a somewhat common 15-17 issue.
 
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Jim Bronson

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I am get a P0300 and P0308. Random misfire and cyl 8.

I am pretty sure it’s a failure of the intake manifold runner plates. What year is your car? Seems to be a somewhat common 15-17 issue.
Mine is a 2017, and I get those two codes too. I plan to take it in after new years. I'm guessing the dealer will try plugs, injectors, and anything else simple and cheap before they remove the intake manifold. This all translates to wasted time and inconvenience for me, as it appears to be a broken runner shaft. I hope they have had some experience with this problem before so they just go right to the runner plates shaft.
 

Shifting_Gears

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Mine is a 2017, and I get those two codes too. I plan to take it in after new years. I'm guessing the dealer will try plugs, injectors, and anything else simple and cheap before they remove the intake manifold. This all translates to wasted time and inconvenience for me, as it appears to be a broken runner shaft. I hope they have had some experience with this problem before so they just go right to the runner plates shaft.
My sentiments exactly. I have an appointment on Thursday. Hopefully they’ve had a few come through with the same issue and they know what it is.
 

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Sounds like we have the same car. This happened to me it would come on and off. They first replaced one of the catalytic converters, this did not fix the problem. Next, after speaking with Ford, they replaced the intake manifold. This fixed it. Mine happened at about 5,000 miles in 2017 now at 15,000 miles and issue has not reoccurred.
 
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Jim Bronson

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That;s good to hear. I just hope my dealer doesn't start throwing parts at it. Surely there is a dealer database of problems and solutions they can reference.
 

Shifting_Gears

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Please let us know how they handle it. Thanks.
Will do. It’s at the dealer now. I gave them the codes I pulled and mentioned the IMRC issue. They didn’t confirm it was a problem but said they’d consider that during testing. Should know something tomorrow afternoon.
 

Shifting_Gears

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Sounds like we have the same car. This happened to me it would come on and off. They first replaced one of the catalytic converters, this did not fix the problem. Next, after speaking with Ford, they replaced the intake manifold. This fixed it. Mine happened at about 5,000 miles in 2017 now at 15,000 miles and issue has not reoccurred.
Good to hear.
 
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Jim Bronson

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I noticed this morning that the recent misfire codes have cleared. Do codes clear by themselves?
 

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16.GT.PP

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I noticed this morning that the recent misfire codes have cleared. Do codes clear by themselves?
The codes will still be stored in history. I had the same codes P0300 & P0308 and would notice a slight occasional stutter with the cruise set at 60 to 65. Then it would go away for a bit and cel would go out then come back. I still had warranty but did not want the dealer touching the car. I found a intake a local guy took off at 1k miles for super charger for $100. Pulled my intake and found the runner control rod broke put the other one on problem solved.
 

Shifting_Gears

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Quick update on mine - dealer was able to retrieve the codes and confirmed the intake manifold is suspect. They’re going to run a compression test to rule out any type of internal damage and if it’s all clear there, they’re replacing the intake manifold.
 
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Jim Bronson

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I got codes this morning on the freeway, and I suppose they are the same ones as before. Mine is under warranty, so I'll be taking it to my dealer. That's what warranties are for.
 

Shifting_Gears

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I got codes this morning on the freeway, and I suppose they are the same ones as before. Mine is under warranty, so I'll be taking it to my dealer. That's what warranties are for.
Just got my car back and it’s smooth as butter.

They replaced the intake manifold assembly and that’s it.
 
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Jim Bronson

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Great news. I'll be making an appointment next week.
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