WARNING
Inhalation of exhaust gas is hazardous to your health. All exhaust gas contains carbon monoxide (CO), and inhaling it can cause unconsciousness and possible death.
Do not run the engine in confined areas (such as a garage) which are not properly ventilated.
If you think that exhaust gas fumes are entering the vehicle while driving, have the cause determined and corrected immediately. If you must drive under these conditions, drive only with at least one window fully open at all times.

Do not depress the accelerator pedal when starting the engine.

The catalytic converter preheats for up to 30 seconds after a cold start. The sound of the engine may change during this time.