P0300/Rough Idle

[Lane_barber]

Had P0300 come up finally after battling rough idle past few weeks. 2018 GT MT-82, Car will idle pretty rough on cold starts seems fine a WOT, I’ve noticed at idle my AFR bounces from around 14 then goes to 20 after idling for about 15 mins then will go back to normal. Also sometimes feels sluggish when taking off from stop…Read lots on VCT, and IMRC I’m thinking one or the other. I’ve changed plugs, cleaned MAF, cleaned throttle body, checked for vacuum leaks

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[NGOT8R]

Did you install a new clutch just prior to the P0300 DTC? If so, did you perform a crank relearn procedure?

The other thing you can check (since you suspect it could me IMRC related) is, pull the IM to make sure the flaps move properly and confirm that the linkage isn’t broken.

 

[tdstuart]

Doesn't sound like imrc to me as they should be in the closed position at idle but I'm not 100% sure on this.

What is done to the car and have you changed anything recently?

 

[Lane_barber]

Doesn't sound like imrc to me as they should be in the closed position at idle but I'm not 100% sure on this.

What is done to the car and have you changed anything recently?

I really haven’t done anything to it recently I only mods I currently have is roush axle backs h-pipe and a CAI, also changed oil recently to see if that may help but unfortunately it didn’t

 

[Lane_barber]

Did you install a new clutch just prior to the P0300 DTC? If so, did you perform a crank relearn procedure?

The other thing you can check (since you suspect it could me IMRC related) is, pull the IM to make sure the flaps move properly and confirm that the linkage isn’t broken.

]

Did you install a new clutch just prior to the P0300 DTC? If so, did you perform a crank relearn procedure?

The other thing you can check (since you suspect it could me IMRC related) is, pull the IM to make sure the flaps move properly and confirm that the linkage isn’t broken.

nope no new clutch and may try pulling IM to at least see if it’s something obvious thank you

 

[NGOT8R]

Which CAI kit (tune required or no tune required version)?

 

[Lane_barber]

Which CAI kit (tune required or no tune required version)?

C&L No tune

 

[tdstuart]

And its not throwing any other codes? No wrench light?

 

[Lane_barber]

And its not throwing any other codes? No wrench light?

Nope only P0300 no other lights or anything

 

[NGOT8R]

More reading for you.

https://www.mustang6g.com/forums/threads/p0300-issues-after-imrc-lockout.178809/

https://www.mustang6g.com/forums/th...ing-factory-components-is-it-possible.182920/

FYI, the the flapper rods for each bank of runners is square and it fits into a square hole in the sensor. I can see how over time, the square hole in the sensor can become rounded and as a result, render the flaps inoperative.

 

[tdstuart]

More reading for you.

https://www.mustang6g.com/forums/threads/p0300-issues-after-imrc-lockout.178809/

https://www.mustang6g.com/forums/th...ing-factory-components-is-it-possible.182920/

FYI, the the flapper rods for each bank of runners is square and it fits into a square hole in the sensor. I can see how over time, the square hole in the sensor can become rounded and as a result, render the flaps inoperative.

Now that I am thinking the flaps default open right? So if it failed open that could cause issues at idle like what you linked.

 

[Pistol_91]

IMRCs are closed at idle could be a really bad vacuum leak but id assume it's something to do with plugs or a coil possibly

 

[NGOT8R]

Tricky icky stuff. I’m glad I deleted mine. I wish I had done it much sooner, as in when I first had the car tuned, as I could have saved myself $150 in tune revisions.

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