That's a really helpful page, Spike. Thank you. Hopefully a lot of this, such as measuring block values, will also apply to the A2 FSI ECU.I'm also in the 'minimal knowledge' category when it comes to petrol A2s but came across this general VCDS diagnostic guide which covers O2 sensors and Cats - www.vwaudiforum.co.uk/forum/archive/index.php/t-140004.html
Can't vouch for its accuracy but the test procedures look promising
Thank you, Andrew. Have you a recommendation on how this might be best achieved?I would say understanding the low lambda value should be the first port of call for diagnostics.