Initial morning start, idle is too high.. last 5 seconds

How to idle down only that phase of morning start

 

They do run a little fast on start up, then slow down after about twenty seconds or so.

 

Agree with Wingrider;

Mine stats at around 1200 revs, then drop over the next 10 - 15 seconds; that is when I engage Drive. I also get a "Death Rattle" for about 3-4 seconds; I understand that it is caused by loss of oil pressure in my VVT units as they attempting to peg the Cams (although I could be wrong about that)?

 

When I first got mine it had fresh Mobil 1. Switched to Castrol Euro blend 0-w40 after a 1000 miles. This took a while, car had suspension rubber rot. Spent way more time on jacks than road at first.
Switching to Castrol made start up quieter. Less banging and clanging.
After a couple changes switched to Rotella. Seems a little quieter still. No noises in the morning.
Have not tried M1 again to see if noises return on startup.

 

Has recently had new gaskets replaced on the entire top of the motor and under the supercharger, new plugs, and when I got it back from this work being done to it my initial starting idol was Higher ..on the initial start I don't want it to idle that high it appears to me it will eventually throw a rod

 

What is the rpm it revs up to on startup? A vacuum leak will speed up, but should not get better after 5 seconds. ECM should prevent this. Maybe it does, just takes 5 seconds.

 

You can supposedly re-calibrate the throttle motor/signal on the throttle body with a battery disconnect/reconnect. There is a reostat in the throttle pedal that signals a motor on the throttle body. Torque Pro (OBD2 App) sued to show my throttle at 20% with the pedal untouched. Upon reconnecting you do a throttle range input,then let it idle for a few mins to calibrate the drive-by-wire accelerator. After doing this several time my throttle was calibrated, but it never stayed that way, so it may not be worth the effort.

Here is a thread that discusses the re-connect procedure and throttle travel calibration as well as IDLE CALIBRATION - Its for XK models, but includes the 4.2 Liter. Easy thing to try and could put the idle right for you:

https://www.jaguarforums.com/forum/x...ect-faq-74146/

https://www.jaguarforums.com/forum/a...connection-pdf