Q: Intake manifold gasket problem - 2015 Dodge Journey

Your vehicle has an upper intake manifold and a lower intake manifold. Both are injection molded plastic assemblies. It is not clear which one is leaking, but in all events the leak should be confirmed by a professional because your car is relatively new, although it does have relatively high miles for a one year old car.

Generally, vacuum leaks degrade the efficiency of the engine, can cause the engine to misfire, and can also affect the operation of any vacuum controlled devices on the vehicle, including most importantly engine management devices such as the EGR system. Due to these negative effects on engine performance and efficiency, the answer to your question is that the leak, if it is confirmed, should be fixed as soon as possible.

I recommend having a certified mechanic, such as one from YourMechanic, come to your location to replace the intake manifold gasket.