Hi, I'm new here. I'm trying to get my car to pass smog. It's a few hundred over on the NOx at 15MPH, but it just passes at 25MPH. Here in california we have the roller test. Supposedly my timing is slightly retarded, and the idle is a little low, so I guess the smog guy knew what he was saying when he said the timing was off. Any suggestions?

I'm thinking it's the PCV valve, timing,and the fact that I didn't run the car very much to heat up the cat and engine. o2 sensor looks new, and it's a new style cat. I haven't tuned it up at all.

THANKS!!