2020 Toyota Corolla engine problems

We rented a 2020 Toyota Corolla from Hertz at the McCarran Airport Las Vegas NV and almost past out while driving due to Carbon Monoxide poisonings. My wife was sick 3 out of the 4 days while this auto was being driven in our possession. At first our sickness was thought to be motion sickness or maybe from something we ate. It wasn't until we drove this car out of town when we both my wife and I started getting very sick weak dizzy and vomiting. We tried to drive out to the Hover Dam but stop about 10 miles short.

Engine abnormal shift downward while driving regularly. I feel the shift is not smooth even feels like a defect in the engine shift system 17,000 miles mostly happens regularly driving on city streets and a bit less happens on the parkway but does happen. The shifts are hard to ignore I remember the very time I felt it on 10,000 miles and it would able occasionally and now it's happening even more frequently than I can possibly say this is an ongoing defect and growing to be a problem even more so.