I have a 93 Mazda Miata i bought 2 years ago. It passed inspection initially but when reinpsected last month with new emissions tests, it failed the NOX and CO2 standards. Is there anything I can do without taking the car to a mechanic to get it thru inspection?
Motor (stationary and mobile) emissions standards are set by the EPA (Environmental Protection Agency) of the U.S. Gov. This is what the EPA says about CO2 emissions: http://www.epa.gov/OMS/climate/420f05001.htm
In short form, your fuel mileage is lousy. To improve it, your engine needs tuned. Change spark plugs, air filter, pcv valve, and check the operation of the EGR valve.
The NOx may be high because the EGR isn’t working so good. Also, you may be able to lower NOx if you retard timing a touch, if it’s adjustable.