Hi all,

I took my 96 civic ex (d16y8 engine) in for a smog check today and it had one bad result on the NO reading @ 490 at lower rpms, but ok at higher rpms, and all the other readings like HC, CO are all well below the average. I have already tuned up the car by changing the air filter, spark plug and wires, cleaned cap/rotor (replaced not too long ago), changed oil/oil filter/pcv valve.

Checked timing.

Right before the test I filled it up with Shell 91 high octane gas and added a bottle of Chevron fuel injector cleaner.

What could I have done to lower the NO reading? I don't know what else to fix/replace....

I live in California, where they just started an 'enhanced' smog check procedure not too long ago that is more demanding than the previous one...

Thanks for any ideas...

civicfan8 in the San Francisco Bay Area...