From my searching it appears you're incorrect. Combustion produces carbon dioxide. The carbon monoxide comes from incomplete combustion, which it seems there is always some of, but regardless, it appears most of the gas produced from combustion is carbon dioxide.

edit:

from https://www.sciencedirect.com/topics/engineering/carbon-monoxide:

Carbon Monoxide CO is a product of the incomplete combustion of carbon-containing compounds. Stationary combustion sources produce CO, which is oxidized to CO2 while dispersing in the air from the stationary source. Stationary sources of CO are significant only quite near the source.

Most of the CO in the ambient air comes from vehicle exhaust. Internal combustion engines do not burn fuel completely to CO2 and water; some unburned fuel will always be exhausted, with CO as a component. CO in vehicle exhaust can be reduced by using partially oxidized fuels like alcohol and by a variety of afterburner devices. It tends to accumulate in areas of concentrated vehicle traffic, in parking garages, and under building overhangs.

So it seems any CO which was released oxidizes in the atmosphere.

from https://www.chemicool.com/elements/composition-of-air.html:

Nitrogen 78.08% Oxygen 20.95% Argon 0.93% Carbon Dioxide 0.04% Neon 0.018% Helium 0.00052% Methane 0.00018% Krypton 0.00011% Hydrogen 0.000055% Nitrous Oxide 0.000032% Carbon Monoxide 0.00002% Xenon 0.0000087%

Looks like we shouldn't be worried about the concentrations of CO in the air.

And from https://en.wikipedia.org/wiki/Exhaust_gas:

Component Emission Rate Annual pollution emitted Hydrocarbons 2.80 grams/mile (1.75 g/km) 77.1 pounds (35.0 kg) Carbon monoxide 20.9 grams/mile (13.06 g/km) 575 pounds (261 kg) NOx 1.39 grams/mile (0.87 g/km) 38.2 pounds (17.3 kg) Carbon dioxide - greenhouse gas 415 grams/mile (258 g/km) 11,450 pounds (5,190 kg)

If this chart is correct then carbon monoxide emission from a passenger car looks to be about 1/20th the carbon dioxide emission.