Pulling my hair out to find a solution to an idle issue i'm having, any help would be greatly appreciated! I have a 2011 XF 5.0 V8 with 105000 miles. Over the last two years I've vitually replaced most of the top engine components from the head gaskets up and only have a lingering idle issue driiving me crazy. The car runs perfectly with zero DTC codes whatsoever. The issue is after cold starting the car and when the idle settles back down to normal the idle starts loping which you can feel and see to tach rise and fall in a pefectly timed pattern. However the idle issue completely goes away when the gear selector is in drive or reverse while holding the brake pedal and I never have any issues while excellerating or driving. Like I mentioned most sensors, all 8 coils, spark plugs fuel injectors have been replaced with new. The only thing I have noticed is when the MAF sensor on the passenger side is unplugged a noticable idle surge happens but doing the same thing to the MAF sensor on the drivers side no change in idle occurs. I have replaced the sensors and swapped them as well and the same thing still happens. I even went as far as checking continuity in the 5 wires from the drivers side MAF sensor and ecm and all wires seem to not be broken between the sensor and ECM. Anybody experience this same issue with a recommendation where to start? Thank You!

 

Could be the throttle sticking. Clean throttle body and MAF sensor with approved cleaning solution. CRC is the brand that I use for cleaning. Very cheap and are available in spray cans

 

You might have better luck posting this in the X250 thread.