Quote Originally Posted by Major Motion
if N0x failed it could be your exaust gas recirculating valve. the only thing it does is control you n0x levels. if that doesnt work. contact 350zftw
Nice try but none of the B series Honda engines come with an EGR. Besides, even if it had EGR and it worked, the numbers would still be high. The main purpose of the EGR is to assist in reducing the NOx, not control it.

The issue with this car would be the catalytic converter not oxidizing the way it should. How big is the converter/exhaust and is it still in the stock position?