Engine startup 10 second misfire

[Shawn2018GT]

My 2018 Mustang GT, after sleeping over nite, misfires after startup for 10 seconds, then the problem is gone. Code pops for random misfire. Every time after a sitting for hours.
My diagnosis, at 100,000 miles, is a slow leak in an injector. They say to replace them at 100,000 miles. But there are 16 of them! 8 inside the manifold, high pressure direct injectors. 8 on the outside, low pressure port injectors. Which ones of each of the 2 types should I get?? Can I replace and forget them, or do I have to re-tune it??
Please advise.

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[Paddles]

Have you had your car for all 100k miles? Do you have the A10? I'm guessing you won't need a tune for factory replacement injectors. Also, this could be wrong but I think I read once that only 8 injectors are used for startup/idle

 

[K4fxd]

I think I read once that only 8 injectors are used for startup/idle

But it could be any of the 16 injectors leaking causing the problem

 

[Paddles]

But it could be any of the 16 injectors leaking causing the problem

Good point, plus at 100k it's probably best to just replace either way.

 

[sk47]

They say to replace them at 100,000 miles.

Hello; This may be a dumb question but why would the injectors need replacement at 100K miles? Other cars go much farther than that on injectors.

 

[Snakebyte]

Hello; This may be a dumb question but why would the injectors need replacement at 100K miles? Other cars go much farther than that on injectors.

I'm not sure what "other cars" you are speaking of.

 

[sk47]

I'm not sure what "other cars" you are speaking of.

Hello; I personally have had two fuel injected vehicles with over 140,000 miles on the original injectors. Both Nissans with the 2.0 liter engines. One I continue to own, the other after I sold it known to have well over 200 K miles.
While i cannot testify about the vehicles I have known of folks who have well over 200K miles. My neighbor has a F-150 with over 300K miles. Of course it may have had injectors replaced as he bought it with high mileage.

 

[Mach VII]

Are you guessing you have a fuel leak down or did you prime the system and watch pressure with a gauge?

 

[Basspro302]

Buy a bore scope pull the plugs and scope each cylinder after keying up the fuel pump. You should be able to see fuel pool in the cylinder.

 

[Snakebyte]

Hello; I personally have had two fuel injected vehicles with over 140,000 miles on the original injectors. Both Nissans with the 2.0 liter engines. One I continue to own, the other after I sold it known to have well over 200 K miles.
While i cannot testify about the vehicles I have known of folks who have well over 200K miles. My neighbor has a F-150 with over 300K miles. Of course it may have had injectors replaced as he bought it with high mileage.

Oh...Ok! I was talking about manufacturer recommendations, which @Shawn2018GT stated, and you were replying to.

I have seen vehicles last longer as you have stated, and love it when they do.

For @Shawn2018GT, there are several factors that may be in play IF the injectors are the source of your issues, such as extreme climates, fuel used, or type of service, and etc.. While injector cleaning may be possible, if I'm going through the labor to remove them, I'm personally not going clean them. I'm going to get high quality injectors to avoid visiting that type of service again any time soon.

 

[Shawn2018GT]

Hello; This may be a dumb question but why would the injectors need replacement at 100K miles? Other cars go much farther than that on injectors.

I’m reading maintenance sights and the writers keep saying injectors wear out, and 100,000 miles is the recommended change-out.

 

[Shawn2018GT]

Are you guessing you have a fuel leak down or did you prime the system and watch pressure with a gauge?

I have no tools to test it. I’m guessing based on mechanics advice. Quite a few mechanics, but only one knew mine has 16 injectors. . I’m hoping someone can give me great advice and recommend the best and correct parts.

 

[Shawn2018GT]

Have you had your car for all 100k miles? Do you have the A10? I'm guessing you won't need a tune for factory replacement injectors. Also, this could be wrong but I think I read once that only 8 injectors are used for startup/idle

I bought it used at <5000 miles. It’s a Canadian version brought into Washington State for sale there.

 

[K4fxd]

Find someone who can test and give a proper diagnosis.

 

[Shawn2018GT]

It is the Premium Plus with the 12 inch screen. It WILL NOT show speedometer in mph. ONLY kmh

it also comes with a freeze plug electric heater.
These 2 things make it Canadian

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