I aquired a 1998 xj8 at auction so no history is known. I was getting a restricted performance message error code was missfire on # 7, when i resolved the problem the radiator overflow tank was leaking and created a carbon track onthe spark plug boot for that plug. the car is running fine know

 

All very interesting Roy, and congratulations on sorting out your car singlehanded, but shouldn't this have been posted in the X308 forum ?

 

you are probably correct