Your Camaro could have failed for high NO due to two things mainly. The
first would be a defective EGR system or the EGR valve. EGR stands for
exhaust gas recirculation. Your Camaro's EGR system includes the EGR valve,
EGR control system and EGR ports/passages. Your Camaro EGR system
recirculates burned up exhaust gases back into the combustion chambers. This
allows the engine to run cooler and keeps NO levels within limits. The EGR
valve should normally be inspected to ensure its proper operation. Carbon
deposits often plug up the EGR passages and cause the valve to stick.
The second problem which could be causing your Chevy Camaro to fail for high
NO is lean fuel or lean air to fuel mixture. NO is created when an engine's
combustion chamber temperatures rises above 2500F Fahrenheit. When not
enough fuel gets to the engine a lean fuel condition is created causing the
engine to run hotter then normal and creating NO. The lean fuel conditon
should be seen in the CO numbers on your VIR report. Anything between 0.00
and 0.03 percent CO is too lean and needs to be diagnosed.
