Driving the XK this weekend she started slow, so I thought to myself, OK, Battery soon, looked original. Wife was driving tuesday for work. Shut it off in a parking lot then when she tried to starty back up, nothing. Then starting getting wacky messages on the display. No clicking or anything. Ran over with a truck and tried jumping it, finally started to at least click. Grabbed a battery at sears (closest place) and started right up. Seems like the battery just dropped out. 5-1/2 years on an original battery not so bad.