What do you do when check engine light comes on
Take the vehicle to a local auto parts store such as O'reilly Auto or similar and have the trouble codes scanned. This is a free service. Then armed with the trouble code(s) do some online research to help in determining the problem. Also you could take the vehicle to a local mechanic for diagnosis.
Listen to the guy over my head !
Premium fuel is not the answer as there is no difference in it's shelf life versus regular fuel. Fuel stabilizer is a good idea as well as keeping the tank pretty full. It can not be known that the OP has a gas cap issue due to us not knowing what the trouble code(s) are. Guessing and not paying attention to the details is not helpful.
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