Your symptoms sound like bad shocks/struts, The old style test was to bounce your car and see if it still bounces when you stop. Unfortunately that is not a good test, by the time that happens your shocks are long gone. We recommend them every 75,000 miles to keep your car riding like new
RepairPal Certified shops can diagnose and repair your 2000 Jaguar XK8. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.