So I've had a couple odd happenings with my XF within the last two weeks. About a week ago, during a cold start, the revs tacked up to 3k immediately and stayed there. I go concerned and shut her down. Restarted and same thing, but normalized when put into gear. No codes were thrown, and no CEL. It ran fine the rest of the week.
A week later the same problem occurred, very high revs at start up, two days apart. I though maybe MAF issue, so I removed and cleaned both MAF's. as I was removing the MAF on passenger side, I noticed the air duct that feds the box from the cool air snorkel was ripped. I removed the duct entirely until I can find a used one or make one myself. I have not had the high rev issue reoccur since cleaning the MAF's, but yesterday on the drive home, I got a CEL, and the codes were lean bank 1 and lean bank 2. Since the duct feeding the airbox is before the MAF and filter, I would not think it could affect the sensors, but I am not sure what else may have caused that code? O2 sensors seem fine, and no others codes. Maybe the MAF's are going bad and it's just intermittent, and that caused the high revs and lean codes?

Has anyone dealt with a similar excessively high rev issue or similar issues as me?

 

Check for any air leaks upstream of the MAF sensors - the plastic pipe from the sensors to the air intake often splits over time.

Remember that the MAFs work by measuring airflow across it (in a pretty rudimentary way too, just based on how much a heated wire filament cools with air passing over it) so if you have a split in the intake past these sensors, the air will get sucked through here and the engine management won't have an accurate idea of how much air is going into the intake and is struggling to balance the fuel etc as a result.

At least, that's my guess.

 

Thanks Davetibbs. Yes I did check upstream thoroughly but cannot find any issues. I have the solid mina intake and the silicone mating pieces are very secure to the air-boxes and throttle body. No air getting in there after the MAF. That's what made me scratch my head and think maf's going bad. although in my experience on previous cars, they don't go bad over time, they just go bad and need replacement.

I'll see what the drive home today brings me.

 

Those codes usually but not always mean an air leak. To check, with a hot engine park and look at the fuel trims at idle then rev to about 2500 and see if they drop markedly.

The thing you can do as well is read the freeze frame data, which will show the relevant other data as the codes flagged.

 

thanks for the suggestion JagV8, I will try to get readings of stft and ltft tonight.

 

So after sitting at work for 10 hrs, I got the cel at exactly the same place as yesterday, sitting at a stop light about a mile from work. Went to the store, cleared the code, and couldn’t get it to come back on I. Another 39 minutes of driving. Slow driving, spirited driving, idling, nothing made it return.
Sorry for the poor quality videos, I only had my handheld device in the car ...

 

Codes

 

files too large, ill need to rethink how to post

 

 

 

 

 

 

Those are so hard to look at. So hard to wade through

Use Search to see what others did and advice given on air leaks.

 

Sorry for reviving an old post but I just wish to update some experiences I have had in the past few months with the similar situation of over-revs on startup on my 2014 XF 3.0 SC AWD.

Back in December we experienced some really cold weather (-43C) and although the car is parked in the garage which is normally above freezing, this time it was (-8C) inside. The car started easy enough but had a higher than normal idle speed. Over the next few days and especially after sitting for a few hours outside it would idle high. I assumed because of the cold but it warmed up to (-2C) and still seeing high revs at startup. It can range from governed down to 2800 rpm for a minute or so then slowly resides to normal idle.

When the engine light popped on it went to the dealership, they reset it and tried to recreate but no luck, they did find that bank 2 O2 sensors were the flagged issue but they couldn't get it again. The drive home was fine and the little bit of running around was without issue. The next morning same problem. I was able to get it back in and it was determined to only occur during a cold start, they informed me of the TSB for changing the 02 sensors and they were covered under warranty so they ordered them in and we are just waiting for their arrival and to be installed,

(I ran my back-up reader and received both a P2189 and P2187 codes, unfortunately I was having issues with my SDD so I could not get much more for information other than these generic codes which covers everything from 02 sensors to COV and MAF as well as damage to the intake integrity)

As long as I keep the garage heated and short parks outside, all is fine but when the system is cold, it has the high idle.
Once this has been corrected, I will update so if others have a similar issue, they might have something to start from.

Kevin

 

Try to replace these...

 

Thank you Jssaab,

I don't know how I missed all the posts about the PCV valve cover. For less than $30 delivered it definitely will not hurt to swap out, especially when I'm getting word from the dealership that the O2 sensors could be a while yet.

 

I’ve never seen O2 sensors cause fast idle but I have seen PCV do that and cause O2 reading off at idle.

Best way to check is to see if O2 readings go back to normal as soon as you are no longer on vacuum ( under boost on a SC car)

so as soon as you accelerate your fuel trims should go to 0-5 of so %

j

 

Yes please no more phone pictures!
Post the actual codes as 10 pages of pictures don't really help and it's very hard to follow.
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If the pcv covers do not fix your issue, check all your breather hoses and the little holes into your rocker covers that they clip onto. Over time they can crack and draw air. This can cause air leaks and throw the exact codes you are reporting.

It was mainly on the s type that I sound This but I don't see jag having bothering to fix it as it usually doesn't happen in the warranty period ..