Hi Dave,

There has been plenty of discussion on the standards of Cats on UKAT. They had to comply with an EEC Standard (last year I think) but even then there were exceptions to the these standards. In other words, a Cat can meet these standards and still not be up to the job. To save time and any misunderstanding, I always insist a Cat is fitted from the Main Dealers otherwise I am not interested in any repercussions.

However..... I am interested on how the post cat sensor is mirroring the pre-cat sensor which as you rightly say means the Cat is inefficient but the emissions were all within spec. I would have thought they would be outside spec to prove the inefficiency of the Cat. I hope that a "learned" friend will come along soon and explain why my assumptions are incorrect.

Regards

Pete M