1996 xj6 with 145000k

hello fellow jaggers,

Recently ive been getting a misfire with codes p0300 and p1314... I understand that p1314 is cylinders 4, 5 and 6 catalyst fault but why arent i getting codes for a specific cylinder(s)? What could be the culprit for this? How am i supposed to know which are misfireing and what could be the causes? Im new on the ignition aspect of my jag. Ive never had a problem here til recently.

If it helps at all i get a p1187 code that comes and goes.

Cheers.

 

The X300 is known for not displaying misfire codes. One way of checking is to remove the cover and observe the the coils in the dark, but that is also no guarantee.
Removing the coils from the plugs and checking for oil in the wells can often identify a cause for misfire, and of course, disconnecting the coils one at a time to see which one has no effect should be specific.
The PO of my XJ6 had a misfire and ignored it because he was in Florida for tha winter. He had to replace the cat. which eventually melted down.