It could be as simple as a gas cap or bad cats... There's no one thing that's more common than the rest without knowing more about your car
You will have to have a code scanner hooked up to your vehicle to determine the cause.
Mine was the vacuum vent in the engine. My car isn’t even 2 years old yet...
Take it to auto zone for free diagnostics... Any auto zone I think is catalist converter or gas cap
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