no thermostat will make the car run cooler and richer which will make the hc's go up but in THIS case his hc's are fine. I was talking about possible causes of nox which is why i mentioned it. What happens when the computer detects it's running rich? "this car's running rich, i better lean it out" and when it leans it out the nox go 3500+ppm, this isn't THIS 300zx's problem i was just giving more educational info that's why i said IF that were the case it'd be more like 3000-4000 which it's not. :P BUT ANYWAYS lol

hc's are 32(120 allowed) co's .02(.67 allowed) 2321 nox (907 allowed)

run car at idle put vacuum to egr valve, if car dies egr valve & ports are good, if egr valve doesn't open with vacuum then egr valve is bad, if egr valve opens and car doesn't attempt to die or die then the egr ports are restricted/clogged. if egr never gets vacuum at all then investigate why the vac switch isn't supplying vacuum, if you don't want to go through the tests and just want your car to pass, buy some cats