engine "fail safe-red" light came on, could only drive 20 mph 2 miles to shop.

I had to have the entire throttle body on my 2001 xjr replaced. It was about $2,500 at a Jag dealer. Afterwards, the car's performance was never the same (it didn't have that 'rip your face back' acceleration any more). They said it happens with increased pollution regulations that cause changes to the (newer) spec. Thank goodness it was covered by warranty. You're lucky. Mine failed at about 65,000 miles. Beautiful car... Maintenance nightmare.