Hello I live in California and went for a smog and it failed due to high NO. I just bought a new catalic converter and it passed excellent with all the other test until it got to the dyno, it passed the 15mph test but once he jumped it to 25mph it failed by like 500 over. Idk why I did a whole tune up when I first bought my accord a year ago new wires spark plugs, new rotor cap and a timing belt change, does anyone know what could be the problem? I was thinking it was the EGR Or maybe I need to clean the ports.. Alot of help would be appreciated.

 

those have known issues with the egr valve ports getting clogged. The egr system is their just to lower nox emissions

 

Ahh Ok thank you. It means alot to get a reply . I will post if it worked and I'll look up a guide tommorow