Stephen Degenkolb

this might help https://jaguarwiringdiagram.blogspot.com/

Watch this thread as I have the same 97 XK8 poor performance warning light comes on. Diagnostic reading showed problem was in Group 2 or Bank 2 – passenger side of engine. This would shut down half the engine after about 3 minutes from engine start. My mechanic's 1st option was to rule out an ignition module fault ( common in older model Jags and an easy check) so he swaped them both around to see if it would cause Group 1 or Bank 1 side of the engine to shut down but it didn't so we have thus far ruled out the ignition modules as being the culprit. Next Sunday, weather permitting, he is going to dig into the electrical side of things so I'll keep you updated.