Help! Misfire again after Ford visit.

[NICK5.0]

Hello all, I have a 2019 Mustang GT 10 Speed. Car is not tuned and i have been afraid from all the issues I've had with it. I have had rough idles, stalling and bad shifts. Took it to ford dealers and they first diagnosed it by replacing Solenoid, told me to comeback if car was still experiencing issues, after a month it was still running rough and stalling, they went and replaced cam phasers. Now days later i got a code P0300 for random misfire detected. I called ford and the Mustang expert mechanic they had working on it was let go.

Im scheduled to bring it in on Monday January 16th but I'm concerned they don't know what the issue even is with the car. What could it be? has anyone experienced this? tried to call a different ford shop but they said if they did something wrong, they wouldn't warranty it. Thanks for your guy's input!

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[Crew4991]

Sorry to hear. Stick with the first Ford shop and let them try to remedy the problem. They are responsible for fixing the vehicle as it is still under warranty regardless if a tech was let go, they have others that will need to check out the car. Unfortunately, you have to give them a chance (even if you do not want to). If the problem continues after the next visit, then I would say look elsewhere for warranty work.

Sadly, this same issue happened to my friend a few days ago on this 2018 10 speed... only difference is his is now out of warranty so he has to pay out of pocket.

 

[Stang 19]

And, all else fails, you could see what Illinois lemon law can do…force a buyback.

 

[NICK5.0]

Sorry to hear. Stick with the first Ford shop and let them try to remedy the problem. They are responsible for fixing the vehicle as it is still under warranty regardless if a tech was let go, they have others that will need to check out the car. Unfortunately, you have to give them a chance (even if you do not want to). If the problem continues after the next visit, then I would say look elsewhere for warranty work.

Sadly, this same issue happened to my friend a few days ago on this 2018 10 speed... only difference is his is now out of warranty so he has to pay out of pocket.

Darn mine is out of the bumper to bumper but still has power train so I hope they can get to the bottom of it. Really sucks haven't been able to enjoy this car in awhile, dealer has been trying to fix it since August.

 

[PartyPatJDM]

I always recommend getting the diagnosis from a ford performance/race shop. The dealers hire people that are usually sub-par unless you find the 1 unicorn dealer. Once they tell you what the problem is, then you go to the dealer and say X is the problem, fix it. We are a ford race shop and see it all the time.

 

[Cobra Jet]

Hello all, I have a 2019 Mustang GT 10 Speed. Car is not tuned and i have been afraid from all the issues I've had with it. I have had rough idles, stalling and bad shifts. Took it to ford dealers and they first diagnosed it by replacing Solenoid, told me to comeback if car was still experiencing issues, after a month it was still running rough and stalling, they went and replaced cam phasers. Now days later i got a code P0300 for random misfire detected. I called ford and the Mustang expert mechanic they had working on it was let go.

Im scheduled to bring it in on Monday January 16th but I'm concerned they don't know what the issue even is with the car. What could it be? has anyone experienced this? tried to call a different ford shop but they said if they did something wrong, they wouldn't warranty it. Thanks for your guy's input!

A misfire can be caused by a lot of things - and not every misfire is detrimental.

Just in general, there are many things known to cause common Coyote P0300 misfires. UNLESS there is a specific DTC thrown, some misfires are sporadic and a code isn't always captured. Even a general P0300 misfire code is too general and will send you and a Tech on a witch hunt.

This thread may give you some enlightenment to Ford's misfire strategies:
https://www.mustang6g.com/forums/threads/good-tech-article-on-ford’s-misfire-strategy.108076/

Granted you had the vehicle checked previously, and yes a P0300 may be a very legit concern to you after getting the car back, but sometimes the P0300 is normal. If you're not satisfied with the last Dealership, if there is another nearby, have them go over the car and see if they can find anything out of the ordinary.

 

[NICK5.0]

Update. Car has been at dealer for 3 days, they finally updated me saying spark plugs are loose according to them and couple mechanics are still looking at the car.

 

[NICK5.0]

Update dealer said 1 spark plug was broken after all 8 were replaced 15k miles ago. They quoted me $390 to replace all 8. After some back and forth, they wanted me to pay 150 for a diagnosis. Luckily got them to replace only the 1 spark plug that was broken but I'm hoping something else isn't causing this issue. Aren't spark plugs supposed to last longer? Or are bad cam phasers and or solenoids caused the broken spark plug?

Fun fact when I checked out they handed me a Red Mach-E. Adding insult to injury.They even said you had the mustang right? I said yes but this isn't a mustang.

 

[2016S550]

so has the broken spark plug been the issue all along? if that’s the case it should have been taken care of the first time and they have caused you a lot of inconvenience…..im sure you have not been messing with the spark plugs and breaking on its own is kind of unreasonable. broken by a mechanic or defect maybe? being under warranty I would be arguing that it should not cost a dime.

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