Smog checks measure the levels of pollutants in your vehicle's exhaust. A misfire can cause your car to emit higher levels of hydrocarbons (HC) and carbon monoxide (CO), which are both pollutants that contribute to smog.
In addition, a misfire can also cause your car to fail the visual inspection that is part of most smog checks. During the visual inspection, the smog check technician will look for any signs of visible smoke or emissions coming from your vehicle. A misfire can cause your car to emit white or blue smoke, which can lead to your car failing the visual inspection.
If your car is misfiring, it is important to have it repaired before taking it for a smog check. You can check for misfires by listening for a rough idle or by feeling for vibrations in the engine. If you suspect that your car is misfiring, you should take it to a mechanic for diagnosis and repair.
