My 2010 reg Jaguar XF 3.0L diesel will, occasionally, after a hot start "hunt" rather than idle smoothly. It's always terminated by a blip of the throttle but if I should happen to drive off at idle you can feel the power surging. The revs may oscillate about once a second 100 rpm or so either side of the regular idle speed.
It only seems to happen when the engines been off for 3 or 4 minutes or so (like after refuelling). If I leave it longer (say 15 minutes) it doesn't happen and if I restart after just one minute it doesn't happen either.
It's going into the garage on Friday but in the absence of any engine management warning I'm not hopeful of them diagnosing anything.
Any suggestions as to cause that I could suggest to the garage?
Tim