Sounds exactly what my car was doing before the injector died. It threw cat inefficiency codes until the injector finally gave out. It would be ok once I let the car cool down but return when the car was brought over 5k rpms.

 

my 400 sport has a faulty injector within 1000 miles, lucky it was replaced and the car has been fine since then. hope you get a happy outcome

 

Wow. My servicing dealer has a whole fleet of loaners, but when those are gone I believe they get extras from a rental place nearby (which may or may not have restrictions) and finally Uber. I’ve always gotten one of their loaners - both Jaguar and Land River. I’ve joked that I’ve driven most of their fleet (XJL, a few Discos, Evoke, XE, XF, E-Pace, Sportbrake and I feel like I’m forgetting one or two). Of course they are the only in-town JLR dealer and with their other two locations outside of town are the only three dealers in Georgia, so lots of volume. I wonder if that makes a difference. Since I’m on mobile I don’t see where you’re located.