Stop using mid grade. The 2.4 is designed to run on regular 87 octane. You will see no benefit to running higher octane (other than draining your wallet faster)
Check your tire pressures. If they are low it will rob mpgs.
Are you in a cold climate? If so, winter blend gas is being used and could account for reduced mpgs. Also are you idling the engine for long periods?
What type of driving have you been doing? Stop and go? Highway? Both affect mpgs.
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