XK8 ABS FAULT LIGHT COMES ON INTERMITANTLY PLUS TRACTION FAULT SHOWS

Number of possibilities. Most likely culprit is wheel bearings. Have these checked. Big heavy car and wheel bearings do take a hammering on XK and XJ's. Once they go, the wheel speed sensors are out of line with the tracking ring and a fault code is thrown. As the TCS uses the same sensor, this also throws a fault. Next in line is the ABS unit (it's hardly ever the main block, but ECU itself, companies on the net offer rebuilt units. Finally it can be the ABS pump unit - but the fault codes will show if this is the case - or you can pull the pump unit plug out of the ABS unit and see if it has continuity with a multimeter - should be a low number of ohms. 8 times out of 10, it is wheel bearing.