High Nox

[lint_rides_again]

I just failed emissions again.
it reads CO2 13.4% O2 2.4% HC 95ppm CO 0.03% NO 3504ppm
I have replaced the air filter, oil and filter, fuel filter, spark plugs, wires. non of witch made any difference. What would be my next move? I tried searching the forms first but didn't find an answer so sorry if I am asking what has been answered before.

 

[99sidude]

What mods if any are done to your car? Could be a bad o2 sensor.

 

[George777]

Did you try playing with your ignition timing? I passed my emissions by doing that. Took a couple tries, but it finally passed.

+1 on the O2...

 

[lint_rides_again]

No mods just a stock z6. I tried timing. Set at 14 deg. BTDC was the best but still way to high.
the O2 sensor was replaced last year to get it to pass.

 

[lint_rides_again]

does a z6 have a EGR valve?