What is this- NPR's Car Talk? Just kidding. I had a pickup truck some years ago that had a check engine light at one point so I got a code reader for it ($100). This is what you need to get first. A hundred different things can cause a check engine condition, it could be nothing or the engine could be about to die. You won't know until you read the trouble codes. I think it will also allow you to reset them so as you fix things you will know what still needs attention.