my 04 XJR just started showing CATS System Fault,, the car drives really rough and firm now,,
the fault seems to come up randomly in curves and on different road conditions,,
also,, i hear weird squeaks from suspension over bumpy roads,,

please,, help!

 

I think your best bet might be to read the jaguar specific codes first. You can get the cats system fault for any number of reasons including open circuit on dampers etc. In my case it turned out to be a lose connection so after I cleaned up the connector in the rear damper it went away.

 

found a loose connection on a front shock,, the issue now is that the car suffersloss of power,,

any idea?

 

Do you mean limp mode -more details please.

 

am not sure its limp mode or even related to CATS issue,, no errors displayed,,
but when i press i hear ticking from engine bay and the car pulls slower than usual,,

cat converters? bad gas?