took apart sc intake scoop and air filter/intake tube. i have now noticed that at rest (idle) the induction intake (throttle) plate is carboned up and does not close completely. going to clean it up and see if that changes things.

 

It may not be that but if you clean it be VERY gentle as the special coating can easily be damaged.

 

yeah, gonna blow that idea off. but here's a nifty youtube on how to destroy your intake with a steel brush:
so the car has thrown the P0456, small evap leak. i'm rushed this morning so i'll ask before i research but i assume there's a connection? i did have this code before and the cap is an aftermarket POS. after tightening it, it hadn't returned thought i was good. now i'll be digging into the evap system. https://www.jaguarforums.com/forum/s...-really-45876/ thanks to brutal for this post. any other advise?

 

I'd start with a good cap.