quattroworld

Hi all;

My TT just failed her emissions test :( with high NOx values. Mods to the car are in my siggy below. So, NOx means high combustion temps, possibly bad cat or O2 sensor, vacuum leak ..... The cat only has about 25k miles on it (Magnaflow 200 cell high flow). No obvious vac leaks, hoses are all in good order. Engine not showing any CELs, so O2 sensor ok (?). Would reverting to stock tune for the test & maybe new/one step colder plugs help? I'm probably going to take the car Bach to the shop and hat does most of my work (3zero3), just want to be prepared to discuss options. P.s - already posted this in the 1.8T forum on VWVortex, just thought the 'mile high' crowd here might have some input!

Cheers,,

John