I have a 2002 xj8 .Periodically it will turn over but not engage. If I leave the car wait a half hour and try again it always starts.
I assume the car believes I am stealing it and has some timer that times out in the security system.
Has anyone had this problem? I've had it in the shop almost exclusively for this problem and spent thousands of dollars with no success. Could it be a problem with the keys.

 

Welcome Psychwiz, please introduce yourself and your Jag in the New Members Forum https://www.jaguarforums.com/forum/n...-intro-must-5/

The Search engine top right is quite useful, but word combinations of course determine outcome. So if you don't find what your looking for, get imaginative. The XK has almost the same electrical and motor setup, so don't be afraid to look there either. In your case I typed in "X308 no start condition" and found this, hope it helps... https://www.jaguarforums.com/forum/x...-start-181618/
For other future endeavors (parts maybe or just browsing), check the top task bar out for tire fitment or the Market Place. There's also the regional section under General Jaguar Forums for events or a local help search. Hope you enjoy your time here....cheers

 

I think it will have PATS and if so then the PATS light would be flashing a code if it thinks theft or the like (not recognising a key etc) is involved.

My guess is it's not - but watch the PATS light (if this model has one as I think).

Another thing it may be is a sensor that's wrong - perhaps misreading temperature. You can look at a lot of them via OBD quite easily (& very cheaply).