HKS Guy 1/3/2011Have you fixed this concern already? Hows the condition of your catalytic converter?
Changing the spark plugs, air filter, fuel filter, PCV valve and oil regularly (or just before an emissions test), checking ignition timing and adjusting the carburetor (if you have an older vehicle) can reduce emissions and greatly improve your chance of passing.
Also, filling up your fuel tank with gasoline that contains 10% ethanol alcohol (many premium grade fuels use alcohol as an octane booster) may help lower your emissions even more. Many areas now have "reformulated" gasoline that contains alcohol or MBTE that adds oxygen to the fuel to reduce carbon monoxide and hydrocarbon emissions.
Just before the test, make sure your vehicle is at normal operating temperature. Take it out for a short spin down the expressway. This will heat up the oxygen sensor and catalytic converter to minimize emissions.