Hi guys, my cars engine light has been on for almost 2 weeks now since i purchased the car I went to see the mechanic and he used his machine to see some codes and says its just the emission sensor due to wrong fuel and should be fine when u use the correct fuel.

Since I recently purchased this car I used 91 later came to know that it uses premium ULP which is 95. As per his instruction i used higher grade fuel. I couldnt find 95 at the moment so i used 98. And also used fuel system cleaner as per his insstruction.

Its been 200kms since and the light still hasnt gone then i went to another mechanic he sajd the same thing and somehow turned it off and after 50km it came back on again.

I am new to cars and not sure what does this mean because the engine light really bugs me out. Any clue or idea on what should i do ? Foni just leave it ?