I have a 99 XJ8. If I punch it, it's fine till I get to 4k rpm, then it's like the rev limiter kicks in, if I let off the gas "just a little" it seems to even out. But, hit it again, the rev limiter/cut out starts. It shifts fine, runs fine, NO codes, nothing. It's not transmission, I'm sure.

Any ideas with NO codes?

 

For a second here I thought I had posted this question and forgot. I'm having the same problem with the same car. I changed out the fuel pump, fuel filter and I'm still getting the issue. I'm half way through a tank of gas with Injector cleaner added and while the problem is slightly better, I'm still missing half the horse power above 4K. I'm a little stumped here myself and not having any codes is making it impossible to track down. I pulled 2 coils from a junkyard ($10 each) and I think I might start swapping those around trying to find the issue. I suspect I might have have a bad injector. No way am I going to pay $250 for 1 injector so I'm going to hit the junkyard again this weekend and pull a couple to swap around. Have you seen the video about cleaning and testing your injectors? Its worth trying.

 

UPDATE:
I pulled my injectors and followed the cleaning process in the video and now my car runs beautifully! I'm shocked at how much power it has at the top end. I did a number of runs from 0-90mph and the engine pulled hard from 1k-7k RPM. No more shuddering or that rev limiter feeling. I'd defiantly suggest cleaning your injectors.

 

Well bug splat, it seemed I had also done the exact thing. I was half way thru a can of sea foam, and it seemed a little better. After your suggestion, I think I'll pull those injectors and follow your suggestion. It was hitting the "rev limiter" at 4k, after sea foam, 4800 rpm.

I got hooked on european cars after my first Mercedes. Now, this is my first Jaguar and I love it! Amazing car.


I have a SL500 two door convertible, wife a E430, and she's already told me she's taking Jaguar. And both of ours are a few years newer than jaguar. Btw, the Jaguar has 70k.