Black smoke

In the absence of other symptoms, black smoke is a sign of burning too much gas. On a car as new as yours, the engine computer should see the results of that, set a diagnostic fault code, and turn on the check engine light. This can be caused by a spark-related misfire that sends unburned fuel and air into the exhaust system. (A misfire should be detected, set a different fault code, and turn on the check engine light). A leaking fuel injector, excessively-high fuel pressure, and even a leaking pressure regulator, depending on which engine you have, are some less-common causes of excessive gas consumption.