[Sherman Logan]

My purely speculative guess is that she went into the garage, started the car, made herself comfortable in the back seat and committed suicide via carbon monoxide

Modern cars produce very little CO. It's a really unreliable way to kill yourself.

Much more effective to run a lawnmower in the garage.

[Hot Tabasco]

Modern cars produce very little CO. It's a really unreliable way to kill yourself.

Any car, modern or not, will kill you if you sit in your garage with the engine running long enough.....I lost an uncle via that method.