The MIL came on. P codes are 2187 and 2189 (too lean at idle, both banks). There were no obvious vacuum leaks so I replaced the manifold gaskets and the intercooler cover gasket. That did not help. Once the car is up to temperature and the idle is at 600 rpm, the engine starts feeling rough. The short term fuel trim on both banks goes to 25% and the long term goes to 50+%. Occasionally I get misfires on Bank 1, Sometimes just cylinder 3, other times all three.Off idle it runs well. The fuel trims are normal off idle. The fuel pressure drops to about 500 psi at idle or when coasting. Peak pressure is about 2900 psi. When I drop throttle, the fuel pressure goes low (500), the LTFT jumps up to about 50. The STFT stays between 15 and 20 when the throttle position is low. I can't find any specs on fuel pressures. I have used both smoke and propane to try to find leaks. I don't get any indications that the fuel vapor recovery system is malfunctioning. I trended the command to the purge valve. It opens when the engine is loaded up, but seems to close when it drops back to idle. The fact that the fuel trims only have to compensate at idle seems to indicate that the leakage is after the supercharger. I am a little puzzled about the misfires; they are only on bank 1. But the lean idle shows up on both sides. The plugs are new and I swapped the coils between the banks.
Any ideas?
I have trends, data captures, videos of operating data if it helps.
Jim

 

Year? I doubt it's an X260 or you'd be taking it in for warranty repair. Guessing though........ First clean or replace the MAF, easy Easter egg, clear codes, test.

 

2016. Out of warranty. I prefer to do my own work.
Anyway, I figured it out. It was the symposer.. The techs and parts guys at the dealer didn't even know what the symposer was for.
They wanted $218 for a new one. I just blanked it off. Problem solved.

 

? How can that be, US gets 5 year warranty on X260.

I blanked off mine as well because I don't like the noise. Where/how did you do it? I put a rubber stopper in the tubing at the rear/top of the engine where it has a disconnect but some engine noise still gets through to the cabin. I think the symposer is dumb but not as dumb as piping in engine noise through the entertainment speakers like BMW.

 

What's a "Symposer"?

and I heard somewhere they kill your warranty if you use an aftermarket airfilter.

I bought used from a dealer with the 164 point inspection that didn't include checking the oil level but I got the warranty with it.

P.

 

Mileage.

 

There is a hose that is connected to the back of the intake manifold (passenger side) that is connected on the other end to the symposer. There is a rubber seal between the hose flange and the manifold that was leaking (causing my P-codes). I made a flat blanking plate and siliconed it the manifold. The flange holds it in place. The connection that you used is a lot easier to access.

 

In Europe, there are very strict rules about allowable noise levels from cars. So the manufacturers have added gadgets to make sounds inside the cabin to emulate the experience. Some makers pipe synthesized noise through the speakers. Renault lets you pick the kind of engine sound (V6, V8, V12...). Jaguar pipes intake noise though the fire wall. There is a diaphram that separates the engine vacuum from atmosphere. Ford uses a symposer, too.
Regarding the warranty issue, I hear these rumors, but I suspect if you tell them your brother-in-law is a lawyer or the consumer advocate reporter for the local new station, they will relent on that one.

 

Doh, didn't think of that because I have such low mileage and think in terms of years.

 

The XF is my wife's car. She pretty much lives in it. She coaches girls softball. I don't want to think about how much her hobby costs me.