What could cause increased hydrocarbon emissions from a vehicle?

Increased hydrocarbon emissions from a vehicle primarily arise from complications related to the air-fuel mixture or issues within the fuel system. An incorrect air-fuel mixture can result from either too much fuel (rich mixture) or too little fuel (lean mixture), leading to incomplete combustion during the combustion process. When the combustion is incomplete, unburned hydrocarbons are expelled through the exhaust system, increasing hydrocarbon emissions.

Fuel system issues, such as a malfunctioning fuel injector that delivers an improper fuel supply or a clogged fuel filter that restricts fuel flow, can further exacerbate these conditions, contributing to higher emissions. Therefore, addressing the air-fuel mixture and ensuring the fuel system operates correctly is crucial for reducing hydrocarbon emissions and maintaining optimal vehicle performance.