Emissions

[livstrong]

pulling my hair getting this to pass failed last fall 3 times and now 2 times
getting readings
IDLE TEST
HC Idle 320 reading Limit 200
CO Idle 1.87 reading Limit of 1

2500rpm TEST
HC 86 reading Limit 200 PASS
CO 0.17 reading Limit 1 PASS

any help would be great

[ThisIsSparTTa]

I'm guessing you're going to be hard pressed to get any help with the lack of information about your car and situation. N/A, TT? Have you pulled ECU codes to make sure it doesn't think something is wrong? Checked your oxygen sensors? Do you still have pre-cats? What cats do you have? What state are you in? Yea...

[livstrong]

Sorry guy got 2.5 down pipes original cats new 02 sensors and I'm in Ontario Canada
1990 300zx tt
Codes 34 knock sensor

[t.mcginley.jr]

Code 34 will cause the engine to retard timing, which IIRC makes it run more rich. Or your cats are bad. Or you injectors are dumping too much fuel. You aren't running super rich but a little more than normal.

You could try the vacuum trick if you just want it to pass, worked for me.

[ThisIsSparTTa]

Vacuum trick = T-ing off balance tube and running a vac tube down a little so it's not obvious that you have a hose disconnected. You're creating a vacuum leak, which will cause you to run lean, which will help you pass. I did this in my Z after having it warmed up, and I passed first try. Don't know if I would have passed without it. Also fixing your knock sensor code will likely help too. Don't go cheap with the resistor trick, buy a new sensor and do it right and protect your engine.

[t.mcginley.jr]

Same, I failed two times in NJ for high HC and CO and passed on my third attempt using the vacuum trick.