Idle fluctuations (feels like it might stall)

[loucas-2021]

I've had this problem for a while but haven't done anything about it yet because sometimes months go by without it happening. But now, yesterday and today, it started happening again. Once the car is up to operating temperature, my car idles at 600 RPM. Now, once the car is warm, idle goes between 500 and 600 RPMs and feels like it might stall. I checked for codes but there aren't any. Based on my research, it could be any of the following or maybe a combination:

1. Vacuum leaks
2. Throttle body
3. Idle air control valve
4. MAF sensor
5. EGR Valve
6. Spark plugs and ignition coils
7. Fuel system

Has anyone run into a similar issue before? and if so, what was the problem? The car has 31K miles on it. Haven't changed the spark plugs yet.

Thanks in advance for any help.

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[loucas-2021]

I just got an estimate from my dealer. About $2k, including spark plugs and ignition coils.

 

[SheepDog]

Your car doesn't have an EGR or Idle air control valve.

What does your air filter look like?
If it's really dirty, it can cause this low idle condition

Any misfires?

Have you tried resetting the KAM by disconnecting the battery?

 

[loucas-2021]

Your car doesn't have an EGR or Idle air control valve.

What does your air filter look like?
If it's really dirty, it can cause this low idle condition

Any misfires?

Have you tried resetting the KAM by disconnecting the battery?

I just recently cleaned it. About a week ago. It looks OK. No misfires.

 

[SheepDog]

I just recently cleaned it. About a week ago. It looks OK. No misfires.

Recently cleaned it- meaning you have a K+N or oiled filter?

Check your MAF sensor for buildup/dirt

Do you have any modifications?

 

[loucas-2021]

Recently cleaned it- meaning you have a K+N or oiled filter?

Check your MAF sensor for buildup/dirt

Do you have any modifications?

I have a green filter from Steeda. I do have the https://performanceparts.ford.com/part/M-9603-M8B kit installed. I changed the original filter with the green filter I currently have. Will check the MAF sensor.

 

[loucas-2021]

Your car doesn't have an EGR or Idle air control valve.

What does your air filter look like?
If it's really dirty, it can cause this low idle condition

Any misfires?

Have you tried resetting the KAM by disconnecting the battery?

Haven't tried resetting the KAM. I think I can do that with the Procal tool that came with the CAI kit.

 

[SheepDog]

I have a green filter from Steeda. I do have the https://performanceparts.ford.com/part/M-9603-M8B kit installed. I changed the original filter with the green filter I currently have. Will check the MAF sensor.

Did it just start this low idle behavior, or has it always done this after you installed the Intake and tune kit?

 

[loucas-2021]

Did it just start this low idle behavior, or has it always done this after you installed the Intake and tune kit?

It started months ago. What's odd is that it will not do this low idle behavior for months and then all of a sudden it started up again. I didn't mention earlier, but I just replaced my battery last week. Not sure how that would cause low idle though.

 

[526 HRSE]

Your signature says you have a CAI with calibration and enhanced throttle body. I'd start there.

 

[SheepDog]

It started months ago. What's odd is that it will not do this low idle behavior for months and then all of a sudden it started up again. I didn't mention earlier, but I just replaced my battery last week. Not sure how that would cause low idle though.

Did you perform the BMS reset when you changed the battery?

There is an idle relearn procedure, never tried it but you might give it a shot

 

[526 HRSE]

If you have the stock parts, try putting them back on and see if the problem goes away. My car will search for idle at times.

 

[loucas-2021]

Did you perform the BMS reset when you changed the battery?

There is an idle relearn procedure, never tried it but you might give it a shot

I didn't perform the BMS reset procedure. Seems like the idle relearn is for an automatic?

 

[SheepDog]

I didn't perform the BMS reset procedure. Seems like the idle relearn is for an automatic?

yeah It can't be done with a manual.

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