Your Pontiac Firebird's CO readings are very high. We'd recommend you start your smog check failure diagnosis there. A smog check repair station will first have to find if your Firebird's Fuel Feedback system is working properly. This will tell us a lot about whether your Pontiac has an electronic problem or a mechanical fault causing high NO and HC. The diagnosis for this fault should begin with inspection of the fuel injection “feedback” system. This includes ensuring the oxygen sensors are working properly, the computer system is receiving the signals from the oxygen sensors, the computer is computing the data properly and sending the correct signals to the fuel injectors to either increase or decrease fuel delivery to the combustion chambers. Along with the oxygen sensors, the manifold pressure sensor (MAP), engine coolant temperature sensor (ECT) and throttle position sensor (TPS) need to be diagnosed as well. These three components control fuel delivery as well.
In this particular case you've indicated your Pontiac Firebird is suffering from both high CO and high NOx, as well. Normally these emissions contradict each other (when CO is high NOx is usually low), which leads us to believe the EGR valve which also controls NOx might be defective, or if you've already ensured the EGR system is working (all passages are free and clear of carbon deposits and the EGR valve opens when vacuum is applied) then consider conducting a cylinder compression test to ensure your Pontiac Firebird is not suffering from high compression. High compression will cause your engine to run hot, and running hot will cause high NO emissions.
