What should I look for in a used Jaguar XK sports?
There's plenty to go wrong and you should expect it to. According to the What Car?/Warranty Direct Reliability Index, Jaguars aren't reliable and are costly to fix. Watch that hood in particular. If the motor fails or the fabric tears, repairs will cost a mint.
Older engines can suffer bore wear - watch for misfires and exhaust smoke as you blip the throttle. Timing chain rattles also need some investigation because a relatively cheap repair to the tensioner can prevent a much dearer engine rebuild.
You may need to budget for rebuilding the gearbox after a few years. If its shifts are anything less than smooth, it's time to spend plenty. Or, perhaps walk away from the car you're test driving.
When buying, a full service history is invaluable, but you should also check that every switch and gadget operates because even minor repairs can mount up. Scratches or rips in the cabin can also cost more than you'd guess to sort out.