Canuk_SiR

I'm just curious if the gap in the plugs has a big impact on emissions. I've failed my first emissions test, and am trying to figure out everything that I should look into to prevent another failure, and so far, have changed out the cat with a brand new one, and run super lean for the test. BUT, will my current plug gap (0.030") be bad? Should I get a new set of plugs, like oem's, and have an oem gap for the test? My first test, I barely failed the 40 kph test, but failed miserably on the idle test.
Also, anyone have any other ideas as to what could help me pass emissions? I've got 1 week to get my car to pass

racerxadam

running too lean can also cause you to fail emissions. here is a pic relating the five measured gases and how air/fuel ratio effects them.

Canuk_SiR

thanks for that chart, it helps alot!
I looked at my readings, and I was way too rich for idle. I logged my test, and I had something around 11.5:1 afr at idle! My car was idling too low, and since I never tuned for a real low idle, it was way too rich..