1993 Mazda MX6 6 cyl Front Wheel Drive Automatic 226000 miles

i have a mazda mx 6 1993 and i was concerned on the engine because everytime a change oil with castrol senthetic still a bit noisy on the engine...that would be normal...? and then there is a blink sometimes for ingine check and just a few second then its gone..is that something going on with the car computer?...thank you