2008 Focus Hunts at Idle

Mandeep Technician Vernon, British Columbia Posted   Latest   Edited  
Question
Driveability
2008 Ford Focus S 2.0L (N) 4-spd (4F27E)
Poor Idle
Idle Surge

Worked on it last week, 2008 Focus 2.0 coming back tomorrow for further diagnosis, hunts at idle. RPM gauge fluctuates. No codes, runs fine off idle. Cleaned MAF, Throttle body, reset the module, Smoke tested no leaks. Any ideas Tia. 

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Mike Instructor
Fond du Lac, Wisconsin
Mike
 

Hey, What are you fuel trims at idle? That may offer some insight into the issue. ~Mike

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Jason Technician
Hawthorne, New Jersey
Jason
 

Ohhh WoW its Mike Becker. πŸ˜€πŸ˜€πŸ˜€. Seems like u right on point Mike with the fuel trims especially since it's good off idle. That would be my guess too. I would check too see if there are any tsb,s related to this issue before u load up the parts cannon. Subaru had one for multiple misfire and what it was was that the alternator was putting out a bad ripple. No warning lights on that one. Just

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Mandeep Technician
Vernon, British Columbia
Mandeep
   

Thanks Mike and Jason. That is my next step when I see it back tomorrow. Did not have enough time to spend last time. Thx again.

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Mike Instructor
Fond du Lac, Wisconsin
Mike
 

Also take a look at the intake manifold runner control system. It's possible to have a mechanical issue in the "flaps" and not code. This could cause a breathing issue.

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Mandeep Technician
Vernon, British Columbia
Mandeep
 

Thanks a lot Mike .

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Jason Technician
Hawthorne, New Jersey
Jason
 

No problem brother but keep us posted as u watch fuel trims. I'll be close by my phone while at work if u have any questions or concerns. Take care

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Mandeep Technician
Vernon, British Columbia
Mandeep
 

Thx Jason, appreciate it.

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Pj Technician
Pleasant Hills, Pennsylvania
Pj
 

I don't want to sidetrack this conversation, but its about time for you to make some more videos. I learned more from your … evap system videos than I did going to OEM training. That isn't a knock on the training I attended. That is just how good that video you made is! And to get back on track, id also check the TPS sensor and see what that is reading.

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Clayton Technician
Liberty Township, Ohio
Clayton
 

I would like to second the idea of looking at the TPS sensor and related TSBs. I'm not sure if this is the correct year range, but Ford's throttle body issues come right to mind. I recently had a Fusion of a similar vintage where a fluctuating idle was listed as a cause for replacement under extended warranty. I was also able to get this car to set TPS codes by giving it varying amounts and

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Bob Mobile Technician
West Chicago, Illinois
Bob
 

I'd look at where the PCV is in relation to the MAF.

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Mandeep Technician
Vernon, British Columbia
Mandeep
 

Thx Bob. Will look at that.

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Chris Technical Support Specialist
Commack, New York
Chris
 

I had seen a focus (like a 2002 ish) have a similar issue. When the ac compressor was commanded on the idle would surge. the compressor field had failed and without the extra load from the compressor the idle would surge. If the ac was turned off the symptom subsided. Not a very common problem, but worth a quick look.

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