Have an issue where upon shutting the car down for 30 minutes -1 hour and restarting the car will do the normal loud start RPM rev, then instead of staying constant and then droppiong down to idle it will hunt up and down until it drops down to low idle.

Also it will randomly throw a code for unexpected RPM. seeing codes
P050b-93
P057-23

 

might be this http://topix.jaguar.jlrext.com/topix/service/document/728035 - anyone know if dealer will charge diagnostic fees to do this, as also need to get the software update for odbii power drain issue.

 

My 2017 v6 does this on occasion, like yours, when restarted after an hour or so sitting. It was just at the dealer last week ( tire rotation, tech always checks codes for me), with no codes reported. I always run 91 no- ethanol, I just thought it was doing its "run-up check" as there were no running issues afterwards.