90 days in on my 08 XK and I've sorted through the common gremlin issues around a weak battery (got an dAGM replacement) and the wet footwell drain problem. Got the CATS Sytem Fault and have been trying to clear it by hard reset with battery terminals, to no avail. I have notice, in addition to the harsher ride, that either the shift points are more aggressive or the fuel mapping/advance is more aggressive, because the vehicle runs much better out of the hole, quicker/more torque. A much nicer performance feel since I am used to the Mopar big block world. It's not as aggressive as the Sport setting, maybe halfway between S and normal D.

Lots of reading here and I can't figure out the best way to clear the code, though I may not be in such a hurry, with the improvement in acceleration. I'm keeping the fuse out (unless someone tells me that's not good) until I can get the right code reader, or last resort - see the dealer. I'll note that the reset didn't create the better acceleration by defaulting the driver inputs either..this happened before the hard reset (and after a second). Any thoughts or advice as to 1. fixing the CATS and 2. what caused this increase in power.