Hi and welcome to the forums.
My take would be that Jaguar made a change in the ECU and they updated the one you have to reflect same.
Have you checked in the coil to plug connections to make sure they do not have any buildup of corrosion in them?
I had a 2.9 that would seem like it was running on 5 1/2 cylinders once warmed up it was fine, #1 plug had corrosion/verdigris, once cleaned it ran on all 6.
It means people like me did what Jaguar wanted us to do, INSTALL NEW EPROMS and reconfigure your car!!!
05-1-26am5 1995 MYRecall R493.pdf (256.2 KB)