19 Gt stalling on lights on drive mode / rough idle

[Jaay_d5.0]

Hi guys
I was wondering if anyone has solved this issue on my 2019 Mustang Gt 10 speed im at 23 k miles with a build date of 7/18 took it in twice to get this worked on it hard to solve the problem when no lights pull up on the dash and this issue is intermittent. So what happens is when im at a full stop at a red light my car starts idling rough making a noise shaking up the exhaust than the rpms start to fluctuate and than they go all the way down and boom it stalls while my shift is on drive. I need to shift to park to run it back on. The first dealership visit i got my cam phasers replaced second visit they retune my roush tune said my power pac level 2 from roush is fine. At first i thought maybe it was a roush thing but it turns out other stock 18-19 mustang Gt are experiencing the same thing? Could it be a transmission issue or is it seriously an engine issue?

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[Rapid Red]

Have you tried to go to natural when it starts to fluctuate? See if it smooths out. That may indicate it is the transmission.

 

[Jaay_d5.0]

Have you tried to go to natural when it starts to fluctuate? See if it smooths out. That may indicate it is the transmission.

I have not actually i will try that out! I don’t know much about transmission but yesterday before i stalled i put it on neutral to rev it and switch it back to drive and drove off starting to believe it has to be the trans. I am the second owner and this car must of been abused since the previous owner was averaging 9 mpg

 

[IrishStallion]

I had cam phasers replaced 1.5 years ago @ 4800 miles on my 18. Had tuner bump the idle on E85 to 750 rpms idle. Still occasionally get that rough idle and has only died once since (now at 12,300 miles). My opinion is it is not the cam phasers.

 

[IrishStallion]

Have you tried to go to natural when it starts to fluctuate? See if it smooths out. That may indicate it is the transmission.

Yep, will not help...

 

[Linkster1666]

I'd check the battery, but that's me.

 

[ORRadtech]

Are your symptoms related to the level of fuel on board? There's an emissions component, the Evap Purge Valve I think, that can cause similar issues. It's said to be related to topping off the fuel tank after the pump auto stops.

 

[IrishStallion]

Are your symptoms related to the level of fuel on board? There's an emissions component, the Evap Purge Valve I think, that can cause similar issues. It's said to be related to topping off the fuel tank after the pump auto stops.

I have heard of this and may be guilty of doing this at the pump. Any links on this one?

 

[ORRadtech]

Google will pull up a bunch.
Apparently the symptoms can be different, anywhere from a slight hesitation to stalls. Mine would drop from idle to a near stalls on the first start after a fill up. It never threw a code. Mines an EB so it may not apply but I'm pretty sure I read where it affects the v8 too.
Good luck.

 

[SHxTGUN]

I've had this issue really bad before. Probably still do to be honest. But to mask it, I have had a tune on the car and my idle RPM is set to higher than stock and I've noticed that helps a ton with the rough idle/stalling because I haven't had it in a pretty long time (months).

Anyways, for the actual issue, have you checked the VCT solenoids? I feel like that is what my issue is. One time I took it to a dealership and they cycled them to clear any debris or whatever else from them and it actually helped my issue for a while. But then it came back, so I feel like if they actually replace the VCT solenoids on my car that hopefully the issue will go away. I'll have to call/take it to a dealership sometime soon before my basic warranty is up from mileage.

But yeah, maybe have the VCT solenoids checked out and see if you can also raise the idle RPM. Any time I go back to stock tune with the stock idle RPM, the issue pops right back up.

 

[IrishStallion]

I have noticed the past couple weeks having a trickle charger on the battery the car is not having those idle issues. It will dip 100-150 rpms max. The trans harsh downshifts coming to a stop dissappeared too. Car is weird...

 

[TLW1022]

Its the cam phasers , sometimes the dealer will replace them under warrantee
Usually happens when the oil is getting close to time to be changed
Oil change seems to help

 

[Jaay_d5.0]

Its the cam phasers , sometimes the dealer will replace them under warrantee
Usually happens when the oil is getting close to time to be changed
Oil change seems to help

My cam phasers were replaced and they did a retune for my roush tune and i am still experiencing rough idles and stalling issues

 

[Elp_jc]

As a side note, a defective fuel pumping nozzle caused to spill fuel all over the floor on my then 3K-mile Bullitt, and haven't had any issues in 1K+ miles (fortunately). So I don't think that would be the cause of the OP's issues.

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