Low rpm misfire stumble

[Scoot61]

Looking for some help, I have a 2015 Mustang gt
Mods
JLT cold air
Gt 350 imrc delete
Stock throttle body
1 7/8 long tubes
3" stainless active exhaust.
The car has been dyno tuned since installing 350 GT intake with locked out IMRC . I got the misfire right after installing the intake, misfire is from around 1500 rpm to 3000 rpm but runs perfect to wot not misfire nothing .
Things I have tried to fix this
Throttle body
Injectors ( OEM )
Spark plugs (OEM)
Tested purge valve
Had back on dyno no change

I know this has been talked about before in forums ,but from what I can see there was never a solution to solve it , so I am hoping that someone can help me out here soon ,or I just go back to stock .

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[Cobra Jet]

Looking for some help, I have a 2015 Mustang gt
Mods
JLT cold air
Gt 350 imrc delete
Stock throttle body
1 7/8 long tubes
3" stainless active exhaust.
The car has been dyno tuned since installing 350 GT intake with locked out IMRC . I got the misfire right after installing the intake, misfire is from around 1500 rpm to 3000 rpm but runs perfect to wot not misfire nothing .
Things I have tried to fix this
Throttle body
Injectors ( OEM )
Spark plugs (OEM)
Tested purge valve
Had back on dyno no change

I know this has been talked about before in forums ,but from what I can see there was never a solution to solve it , so I am hoping that someone can help me out here soon ,or I just go back to stock .

Have you tried to pull any codes? Even if you don't have a hand held scanner, you can get them from the car if there are any stored DTC's:


If you have a 2015-2020 with the ANALOG gauge cluster, you should be able to enter the “Engineer Test Mode”.

Follow this link:
https://www.mustang6g.com/forums/threads/engineering-test-mode.27581/

If you you have a 2018+ with the DIGITAL cluster, you should be able to access the same test mode found here:
https://www.mustang6g.com/forums/th...n-18-digital-dash-old-way-doesnt-work.115231/

 

[Scoot61]

Yes code I keep getting P0300 multiple misfire

 

[Fat_Joe]

Yes code I keep getting P0300 multiple misfire

Any updates on this? I am having something similar happen if you check my previous thread I created?

 

[opengl]

I am having something similar happen if you check my previous thread I created?

 

[Cobra Jet]

Yes code I keep getting P0300 multiple misfire

Check VCTs, O2 sensors, the crank sensor, ground wires, and all wiring harness connectors in the engine bay to make sure the connections are secure. This thread below has the info for VCT's and crank sensor:
https://www.mustang6g.com/forums/th...n2-coyote-with-60k-miles.177596/#post-3586437

DIY to cycling debris from VCT's:
https://www.mustang6g.com/forums/threads/rpm-drops-on-2019-gt.175505/page-4#post-3593500

This thread has the info for the O2:
https://www.mustang6g.com/forums/threads/p0300-issues-after-imrc-lockout.178809/#post-3607516

Aside from the IMRCs, the above areas are the most common sources that can cause the very generic P0300....


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/

Also here is a pdf snip from the Ford Shop manual. which is "Coyote" specific. I'm including it because it gives a bigger picture of how to diagnose misfire events from the generic to the actual cylinder event codes:.
https://www.mustang6g.com/forums/attachments/hd-misfire-detection-pdf.538665/

 

[Fat_Joe]

Check VCTs, O2 sensors, the crank sensor, ground wires, and all wiring harness connectors in the engine bay to make sure the connections are secure. This thread below has the info for VCT's and crank sensor:
https://www.mustang6g.com/forums/th...n2-coyote-with-60k-miles.177596/#post-3586437

DIY to cycling debris from VCT's:
https://www.mustang6g.com/forums/threads/rpm-drops-on-2019-gt.175505/page-4#post-3593500

This thread has the info for the O2:
https://www.mustang6g.com/forums/threads/p0300-issues-after-imrc-lockout.178809/#post-3607516

Aside from the IMRCs, the above areas are the most common sources that can cause the very generic P0300....


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/

Also here is a pdf snip from the Ford Shop manual. which is "Coyote" specific. I'm including it because it gives a bigger picture of how to diagnose misfire events from the generic to the actual cylinder event codes:.
https://www.mustang6g.com/forums/attachments/hd-misfire-detection-pdf.538665/

Hmm interesting, I have seen you post this information around this site a couple of times which led me to purchase new VCT's which come in sometime next week. I have done pretty much everything I can think of to fix my misfire situation. VCT's would be the very last thing to try. Thank you for posting this up!

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