Glad you’ve fixed the problem.
Unbelievable to think someone removed that and didn’t replace it.
I’ve been servicing my S Type and was shocked to see all the shoddy work previous owners or mechanics had done on it. The guy I bought it off didn’t seem the type to work on it, and there’s a history of Jaguar service; therefore I can only assume that a qualified mechanic - probably a Jag mechanic - is either a useless mechanic, very stupid, or just doesn’t give a !Removed!. Crazy. Bolts/screws removed and not replaced, spring clips fitted in inaccessible places, etc. I’ve given it a full service and cleaned the MAP and MAF sensors (MAP was filthy), and now she runs like a dream. I even swapped the spring clips for jubilee clips so that the air intake pipes can be removed easily in future.
Moral of the story? Do as much yourself as you can. Take it to a garage only when you feel completely out of your depth or just don’t have the specialised equipment to deal with it.
Hope your XF is - or will be - running smoothly.
All the best
Marty