Check engine soon light on. oil changed regularly. what else needs to be checked - cjp

Go to autozone and get a check engine light test done, its free. ask them to tell you what comes up on the computer.

The check engine light mainly monitors emission problems and a lot of other variables including timing and engine temperature. Most major auto parts stores scan or will loan you a scanner free of charge. Get the errors code number(s) and post it back here or google them for additional help

It depends on te year and make of car, a check engine light yellow means emissions issues a check engine light red means oil or water temperature problem so depending on which one it is could mean the difference of a major or minor problem. Also if the yellow check engine light comes on and there is a plug fouling then you could ruin your catalytic converter due to a misfiring spark plug. whatever the reason have it checked right away don't let it ruin your car, and if you allow the check engine light yellow to stay on for a long time there can be very evpensive repairs that have to be done cause you let it go and it ruined other componets.