[donmac45]

Hi All, and a Merry Xmas and a prosperous new year to you.

After having all sensors tested thrice, a minor descrepancy showed up on the Auto electricians diagnostic gear. It proved to be on Cyl 6 and changing the plug fixed the problem -yeah.
The Auto-el had never seen a spark plug give this kind of error. (fail at no load) -usually the other way round.
Even tho' it cost me several hundreds of dollars (to change one plug) I am still a happy chappie :-). Must take her for a blat tommorrow!!

Mechanics comment -should have resorted to base principles to start with -ie change the plugs as a matter of course. probably have to agree.

Thanks anyway for all the comments here and elsewhere.
At least I know all sensors/airways/waterways etc are up to spec (did all the suggested remedies)
regards
Don McAlpine