I envision a pipe from the exhaust into the car with all the windows up. Would I need to be in a garage (because I don't have one). How long will this method take? Would I fall asleep or die in a coughing fit?
In my experience trying a garage with my car, I walked and sat in my car. It had been running for probably 2 hours, blankets and the like stuffed in all the door seals to make the gases stay in.
I had time to turn my favorite song on, listen to it entirely, all while my heart started pounding progressively harder and harder against my chest. It started to hurt, and I gasped a painful breath, and I turned the car off. I opened the garage door and let it air out, and sat outside for about 20m to get my air back. For the next day or so, I was really really groggy.
The concentrations werent enough to do what was needed. Even after 2 hours, a 2010 car's exhaust wasnt enough to knock me out in a quick amount of time.