Jag 2.7TD auto

Symptom: Always slow acceleration from standing start, like an extra 1/4 second before moving and a second symptom a wandering (slightly jerky) cruise control (felt as if someone was slightly tapping the brakes), and finally occasionally (once every 10mins or more) suffered from loss of power and traction control light coming on for no reason for a second or so.

This turned out to be the ABS ring (back wheel drivers side) having a slight distortion and actually touching the ABS sensor (you can see some marks on the ring, where it was contacting).
The Diagnostics was reading 50MPH blips which was bringing on traction control (but not long enough to show on dashboard, but occasionally did).

Car is late 2004 and from Wales (damp conditions).

Remedy: Swapping the existing sensors around, from the drivers/passenger.
The sensor was slightly different which does not contact the ring (0.2mm or so?).

Working OK now for couple of weeks.

Hope this helps someone.