I have a 2013 Honda Accord Sport with 115k miles. Since September, my check engine light comes on 5 minutes after I fill up or when the tank gets down to 1/4. It goes off in a couple of days and stays off until I fill up again. My fuel mileage has also gotten terrible.
I got it tested and the code P0420 came up. The guy at Auto Zone (seemingly inexperienced) told me it was the catalytic converter and it would be a million dollars (exaggeration). I went to another place and the gentleman (seemingly very experienced) told me to change the gas cap, which I did. He also said it was not likely to be the catalytic converter because they are made to last longer on relatively newer cars. I thought that worked until the light came on again.
Then I went to my mechanic. He put that reader thing (idk what it’s called; please inform me) and got the same code. He said O2 sensors and/or catalytic converter. While I was there, I got new spark plugs. That was Monday; the engine light came on again this morning (Wed.) when I filled up.
Can anyone provide some insight? I am going to order the sensors, but I do not want to waste the money if there may be a less expensive option. I have experienced no other issues with this car.
Of note: This issue started after I put supreme gas in my car, listening to the ads that said it wo0uld help clean my engine. Ever since then, the light keeps coming on.
Thanks, in advance, for any help provided.