Originally Posted by RISKYB
You mean NOx?
Based on the high NOx and HC I'd guess that the vehicle is suffering a slight lean misfire. NOx is created by high compustion temperatures, and isnt always a indicator of a bad cat. Most likely timing is off a degree or two, fix your timing, do a tune up, and change your oil right before going, and you should be set, if it doesnt pass, then you'll need to get your cat replaced.
Another possiblity is a sticking EGR valve, holding slightly open introducing inhert gas... actually, scratch that, EGR lowers combustion temperatures, not raise them.. late night, sorry about that,
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