I have a stock 1995 Acura Integra that I can't seem to get to pass emissions. The only thing thats done to the car is an aftermarket header.

Here's what I've done to it thus far:
-Oxygen sensor
-Cap and rotor
-Plugs and wires
-Ignintion coil
-Fuel filter
-MAP sensor
-Throttle positioning sensor
-Cleaned fuel injectors

Am I missing something? Could it possibly be the header? Any help would be greatly appreciated!

 

Catalytic converter is most likely on it's way out.

What exactly is the fail?

Drive it for 15min then pull the spark plugs and inspect the ends...
http://www.4secondsflat.com/plug_chart.html

Let me know what you find, post a pic of the plugs if you can. 94