Thank you all, and GoMog looks a great site. The car does have Cats and I'll research testing the Lamda sensors. New throttle cable recently fitted.
Dave, when you say blank off the idle valve, do you mean remove it and blank off the hole in the Plenum, and thanks for the Lloyds tip.
How can I check if it's chipped, there is nothing in the pretty extensive history file.
I should add that at whatever the idle speed settles at, it is always very stable.
