2008 Focus Hunts at Idle

Mandeep from Vernon Technician 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 from Fond du Lac

 

Instructor
 

Hey, 

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

~Mike

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Jason from Hawthorne

 

Technician
 

Ohhh WoW its Mike Becker. 😀😀😀. 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 something to keep in mind

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Mandeep from Vernon

   

Technician
   

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 from Fond du Lac

 

Instructor
 

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 from Vernon

 

Technician
 

Thanks a lot Mike .

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Jason from Hawthorne

 

Technician
 

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 from Vernon

 

Technician
 

Thx Jason, appreciate it.

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Pj from Pleasant Hills

 

Technician
 

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 from Liberty Township

 

Technician
 

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 speeds of throttle input (none present when it was towed in). It would also die off throttle while driving. In the past I had a Fiesta that would sporadically die while driving and set intake leak codes. I pulled the plastic cover on the TB and right near the wipers was a pile of metal shavings. I have heard of, but not seen personally, some where the TB is OK, but programming is required. I didn't look this vehicle up, so I hope this is relevant information. Good luck today! 

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Bob from West Chicago

 

Mobile Technician
 

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

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Mandeep from Vernon

 

Technician
 

Thx Bob. Will look at that.

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Chris from Commack

 

Technical Support Specialist
 

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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