This current thread may be of interest to you:

https://www.jaguarforums.com/forum/s...roblem-224034/


There were two active leaks causing the P0171/P0174 codes. Might give you some ideas where to look.

 

Agree with Karl....if you are sure you have no leaks pre throttle body, then a smoke test is highly recommended....you might have accidentally broke something.....or it just coincidentally showed up....it has to be something affecting both banks..,.you could take off the windshield cowl and crossbrace and get closer to the throttle body area for a better view and possible better ear for the hiss.....all the plastic parts near the throttle body get brittle after a time....even the egr tube can split

 

thank you, today I’ll try to look there.

 

read my current post about my lean banks for P0171 and p0174. I did a lot of troubleshooting to find my vacuum leak.