A smog check repair station will first have to find out why your Toyota Pickup Truck is producing high CO. We believe the high HC is the result of a "rich misfire"; and should lower once the CO problem is fixed.
CO stands for Carbon Monoxide. It is a by-product of incomplete combustion, more then often related to the presentation of too much fuel to the combustion chambers.
A smog check repair center should begin by inspecting your Toyota's fuel injection “feedback” system. This includes ensuring the oxygen sensors are working properly, your pickup's emissions computer is receiving the signals from the oxygen sensors, the computer is computing the data properly and sending the correct signals to the fuel injectors; to either increase or decrease fuel delivery to the combustion chambers.
For more high CO causes visit the link below:
What causes high CO?
