2022 Mustang GT Idle & Performance Issues

[50F4ST]

Hello!

I have a 2022 Mustang GT w/ Performance Package and i’m having a new issue as of about 1-2 months ago. Was told this is Mustang heaven for answers.

Current Mods:
- Speed Engineering Headers
- Corsa Extreme Catback Exhaust
- JLT Cold Air Intake
- Stage 2 Tune by Rob @ Shoemaker Performance

All mods were done by previous owner and checked over by mechanics to ensure proper installation.

Randomly after a nice drive one afternoon, I turned the car on one morning (remote start) and after a few minutes of it warming up, it started to fluctuate it’s rpm. I’d say from 1000rpm to 1500 rpm. Up and down, up and down. Eventually it would get less and less and less (1000 - 1200) (800 - 1000) and then settle at 750-800 as normal once warmed up.

Furthermore, the car seems to lack some pull when cruising at higher gears. If I’m at lets say 45 MPH and I need to speed up a little and give it a some throttle, it seems like it hesitates to go and sounds like its chugging while it’s speeding up. It’s like I hear a “pssh pssh pssh” sound that matches the rhythm of the pulses from the engine.Also, random backfire on deceleration. Lastly, I had a recall for my fuel pump so I changed that just in case it was fuel pressure.

I had 2 previous codes:
P2BF0
P0171

Was told to clear the first one and see if it comes back. Never did. Took it to a mechanic for the second code and was told I probably have a air leak and to bring it back when they werent backed up (2 weeks). I smoke tested the entire system myself (not professional obviously) and I can’t seem to find any leak. I took it to 2 other shops that can quickly put it up on a lift and see if my headers or exhaust are leaking and both say there doesn’t seem to be an exhaust or header leak.

Not sure what more to do.

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[ORRadtech]

Did you data log it and ask the tuner?
Otherwise my internet WAG is purge valve or variable valve timing related.
Do you have access to a decent bidirectional scan tool? They can provide a lot of information on what's happening at the moment.

 

[50F4ST]

Did you data log it and ask the tuner?
Otherwise my internet WAG is purge valve or variable valve timing related.
Do you have access to a decent bidirectional scan tool? They can provide a lot of information on what's happening at the moment.

Can’t ask the tuner unless I pay $350 to retune. I have the carpal scanner and the MAF airflow looks normal but the fuel trims look off. LTFT bank 1 about +23% and bank 2 +19-20%.
Idk if that provides any insight but if there’s something to look for lmk or if there’s a device that’d help let me know and i’ll grab it.

otherwise, i’ll google how to test for those 2 you mentioned. Thank you!

 

[Joe Gonsalves]

Sounds like a vacuum leak, hence the P0171 code, but you did smoke test it. Make sure that the CAI coupling to the throttle body is fully seated and the clamp is tight. The throttle body sits downstream of the air flow sensor and any air leak after the fact will cause a lean condition. Also try cleaning the throttle body and air flow sensor.

 

[50F4ST]

Sounds like a vacuum leak, hence the P0171 code, but you did smoke test it. Make sure that the CAI coupling to the throttle body is fully seated and the clamp is tight. The throttle body sits downstream of the air flow sensor and any air leak after the fact will cause a lean condition. Also try cleaning the throttle body and air flow sensor.

Took a look at the throttle body and its still very clean. I’ll see where the airflow sensor is and give it a clean.

 

[Joe Gonsalves]

Took a look at the throttle body and its still very clean. I’ll see where the airflow sensor is and give it a clean.

It's in the CAI inlet tube just after the airbox.

 

[50F4ST]

It's in the CAI inlet tube just after the airbox.

Oh the MAF sensor i’m stupid sorry.. I cleaned that already before and after smoke testing.. No change.

 

[Joe Gonsalves]

Has the intake been off at some point?

 

[50F4ST]

Has the intake been off at some point?

Replaced the entire intake pipe with the same one just new in the chance that it cracked somewhere.. Apart from that no. Everything was put on and snug tight. Double checked.
I also reset KAM after doing so.

 

[Joe Gonsalves]

I was referring to the intake manifold not the tube. It's possible if it was off at some point the gasket could be pinched. Also, I see the car has headers, do you still have the cats? Could be O2 sensors, but that would throw a different code maybe.

 

[50F4ST]

I was referring to the intake manifold not the tube. It's possible if it was off at some point the gasket could be pinched. Also, I see the car has headers, do you still have the cats? Could be O2 sensors, but that would throw a different code maybe.

intake manifold has never been off. Headers are catless but this issue started after the mods by a good while.

Something I should of added was that the exhaust note of my car on idle changed. It lost its “rumble” or like sounds softer? It doesn’t sound like the pressure is all there unless I’m driving and send it. Genuinely think its the headers but after being told its not idk anymore.

 

[Joe Gonsalves]

Could be the Charge Motion Control Valve and Intake Manifold Runner Control, CMCV / IMRC. It runs on vacuum I believe. If it's stuck in the wrong position then it would affect the idle.​

 

[rickytan05]

Change tuner I also had rob shoemaker and had multiple issues thrown codes I changed tuners and I wouldn’t recommend rob to anyone anymore

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