Won’t start unless I step on gas

Re: Ambient air sensor = Mass Air Fuel Sensor? , if so that will throw off all your Air/Fuel ratio causing lean/rich condition.

Also something to consider ,is your engine affected by carbon buildup ,where by the valves are carboned up causing misfire? .It affects engines that do have direct injection technology. Black smoke = rich condition (too much fuel) , carbon = low volume of air from valves

Did you floor the accelerator on startup?

A faulty ambient air sensor may very well cause the problem you are having at startup. Clear the code before troubleshooting further.

The ambient air sensor has nothing to do with a/c. It monitors outdoor temperature so that the computer remaps the air-fuel mixture in the cylinders accordingly. The idea is that cold air is more dense and contains more oxygen than warm air. If your sensor inaccurately reads the outside temperature as colder than it really is, the computer will deliver too much fuel to the cylinders. Black smoke will come out of the tailpipe.