2019 Mustang GT Auto Very Rough Idle/Engine Stall

[SHxTGUN]

Dealership service rep just called me today and said my vehicle will need the VCT solenoid replaced.

They have to order the part and it won't be in till this Thursday.

Cool, let us know how this does for you. Seems to be a common issue.

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[Jaay_d5.0]

Dealership service rep just called me today and said my vehicle will need the VCT solenoid replaced.

They have to order the part and it won't be in till this Thursday.

Cool, let us know how this does for you. Seems to be a common issue.

How long has it been since you experienced the issues shxtgun?

 

[SHxTGUN]

How long has it been since you experienced the issues shxtgun?

Funny that you mention it cause I actually had some rough idle a few days ago for the first time in a long time. No stalling, but the idle was rough a couple times after I went to chic fil a where the drive thru line was super long with a lot of stopping and going (no idea if that has anything to do with it but thought I’d mention)

The rough idle started happening after all that stop and go stuff so maybe that contributed. But I have taken the car out I think twice since that incident and it’s felt fine those two times. No rough idles.

this issue is super annoying though and it shows that it’s really hard to permanently deal with this issue because no matter how long you go without it (like I did for months), it’s probably gonna come back randomly one day and just be a pain to drive.

anyways I’m hoping that Saleen has his VCT Solenoids replaced and that fixes the issue completely for him and if it does then I probably need to call in an appointment sometime in the next few months for the same thing. It’s gonna be a bit harder for me though cause I need to go through the process of hiding my tune before I do any warranty work.

 

[Jaay_d5.0]

Funny that you mention it cause I actually had some rough idle a few days ago for the first time in a long time. No stalling, but the idle was rough a couple times after I went to chic fil a where the drive thru line was super long with a lot of stopping and going (no idea if that has anything to do with it but thought I’d mention)

The rough idle started happening after all that stop and go stuff so maybe that contributed. But I have taken the car out I think twice since that incident and it’s felt fine those two times. No rough idles.

this issue is super annoying though and it shows that it’s really hard to permanently deal with this issue because no matter how long you go without it (like I did for months), it’s probably gonna come back randomly one day and just be a pain to drive.

anyways I’m hoping that Saleen has his VCT Solenoids replaced and that fixes the issue completely for him and if it does then I probably need to call in an appointment sometime in the next few months for the same thing. It’s gonna be a bit harder for me though cause I need to go through the process of hiding my tune before I do any warranty work.

Ahh i see ! My car was stalling and rpm fluctuating with rough idling at red lights after getting the vct cycle 10 times for any debris so that didn’t help the issue but it seems like after i filled up my engine coolant (since it was so low) it stop the stalling but i had experienced some rough idles and rpms fluctuations after for a bit but it been a few weeks now and it seems to have no symptoms of those issues yet!

 

[SHxTGUN]

Ahh i see ! My car was stalling and rpm fluctuating with rough idling at red lights after getting the vct cycle 10 times for any debris so that didn’t help the issue but it seems like after i filled up my engine coolant (since it was so low) it stop the stalling but i had experienced some rough idles and rpms fluctuations after for a bit but it been a few weeks now and it seems to have no symptoms of those issues yet!

Hey that’s great to hear! Yeah I hope that it works out for you. Keep us updated on how it is after a while and if you get any rough idles (or stalls) again. Maybe the VCT + coolant was all you needed. The VCT cycle did help me for a long time and it is mostly gone now. Much much better than it was before when it rough idled on me almost every stop.

 

[Saleen90]

Just an update, I received my car back today after dropping it off on Friday the 29th. They replaced the bank 2 vct solenoid.

I will post an update after 2 weeks once I have driven my vehicle for a bit.

Drive back to work and no rough idle so far but it was only happening to me after I had driven it for at least 15 minutes so we will see. I am attaching my paperwork so that if this is the fix then anyone else that has the same issue can show the service department without having to take multiple trips to them like everyone else has. I don't know why this is such a problem for them to diagnose and fix.

 

[Jaay_d5.0]

I forgot to mention one time i had a rough idle i was on the gauge where it tells you the battery voltage , engine temp , trans temp etc and i notice when i would experience rough idles / rpms fluctuations the air/fuel ratio would go up and down! Just letting you guys know in case this can point you guys to the right direction i never had any codes thrown yet I’ve own the car for a year and a half now only put 9500 miles i am the second owner. Is it normal when im coming to a stop the air fuel ratio go all the way to 20?

 

[Jaay_d5.0]

I forgot to mention one time i had a rough idle i was on the gauge where it tells you the battery voltage , engine temp , trans temp etc and i notice when i would experience rough idles / rpms fluctuations the air/fuel ratio would go up and down! Just letting you guys know in case this can point you guys to the right direction i never had any codes thrown yet I’ve own the car for a year and a half now only put 9500 miles i am the second owner. Is it normal when im coming to a stop the air fuel ratio go all the way to 20?

My car is at 25000 miles forgot to mention

 

[SHxTGUN]

I forgot to mention one time i had a rough idle i was on the gauge where it tells you the battery voltage , engine temp , trans temp etc and i notice when i would experience rough idles / rpms fluctuations the air/fuel ratio would go up and down! Just letting you guys know in case this can point you guys to the right direction i never had any codes thrown yet I’ve own the car for a year and a half now only put 9500 miles i am the second owner. Is it normal when im coming to a stop the air fuel ratio go all the way to 20?

I think when you're off the throttle and coasting, the AFR will go to 20.0. That's normal.

But I had the same issue with the AFR fluctuations when I had this problem bad a long time ago. Mine would go up and down and the idle was rough, so yeah. I mentioned it way earlier on this thread too.

 

[Jaay_d5.0]

I think when you're off the throttle and coasting, the AFR will go to 20.0. That's normal.

But I had the same issue with the AFR fluctuations when I had this problem bad a long time ago. Mine would go up and down and the idle was rough, so yeah. I mentioned it way earlier on this thread too.

Makes me wonder if ford will ever come up with any tsb on there rough idling and rpm fluctuations issues on there cars.

 

[Saleen90]

Tried my best to convert the video to a gif but you can see how the a/f goes from 13 to 16 quite rapidly. That was always the case when I had the rough idle

 

[Jaay_d5.0]

Tried my best to convert the video to a gif but you can see how the a/f goes from 13 to 16 quite rapidly. That was always the case when I had the rough idle

That’s exactly what happens to mine!

 

[Zinc03svt]

I had my cam phasers replaced around 5k miles. Seemed to fix issue only for 3k miles. The idle issue came back. It has died a couple more times.

Just sold car @ 12k miles. Good luck fellers. ;).

 

[ice445]

Tried my best to convert the video to a gif but you can see how the a/f goes from 13 to 16 quite rapidly. That was always the case when I had the rough idle

It's a partial misfire, that's why it's spiking the AFR. If not all the oxygen gets burned, it will read lean.

 

[Zinc03svt]

It is actually the intake cam phasers suddenly reverting to 0 degrees (watch on ford scanner) causing the rough idle and stall. Tech watched it happen.

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