My engine light on and can't figure out how to fix it

OBD2 scanner. You can typically use them at auto parts stores. They hold your ID while you use it in the parking lot. Figure out what code it is throwing. Research the code on the Internet and by process of elimination find out what part or parts is failing. You might have to run other diagnostics to see what's going bad in your engine. A certified mechanic would greatly benefit you if you can't figure it out. Try not to replace parts that don't need replacing.