Carbon Monoxide Poisoning

No. You would breathe normally as the body acts exactly as though it's getting oxygen.

Now, I suppose you used a garage as an example because someone might have inadvertently walked off and let an engine running. If that were the case, the exhaust would contain more than enough carbon dioxide to prompt you. No car cranks out pure carbon monoxide. Whether you would wake up in time or not is another question.

I was told that this occured recently to a relative of my cousin.

She apparently bought her first electric car. She parked the car in her garage. I guess she incorrectly thought that she had turned the engine off. Apparently the engine was on, running on battery power. When the battery was exhausted the car apparently switched to gasoline power and CO fumes killer inside the house.

My God Gol thanks for that report, it's positively appalling. I hope her family sues its maker for not having anticipated such

Yeah, me too! I always thought the electric motor quit running when you took your foot off the "throttle" pedal.

Thanks Rog for your support, I was sure I was losing it

It might be an idea to invest in a carbon monoxide detector just to be on the safe side.

In many jurisdictions, probably most, in North America, carbon monoxide detectors (as well as smoke detectors) are required by city building codes.