A misfire occurs when either the air/fuel mixture in the combustion chamber does not ignite or incomplete combustion occurs (partial misfire). As a result of the misfire, unburned hydrocarbons (HC) are exhausted from the combustion chamber into the exhaust system, where they enter the catalytic converter. As the catalytic converter converts the excess HC into carbon dioxide (CO2) and water (H2O), catalyst-damaging heat can be created, which could cause the honeycomb element to melt into a solid mass, making the converter ineffective in converting harmful emissions.