Something really is wrong, Things go bad and the light comes on to tell you to check it. Have an OBD II code check done to find out what the problem is.
THIS COULD BE A LOT OF THINGS MAYBE SPARK PLUGS OR A SENSOR BAD TAKE IT TO A GARAGE THAT YOU TRUST AND THEY WILL TELL YOU THE TRUTH THEY MIGHT JUST NEED TO RESET THE CODES SOMETIMES YOU CAN UNHOOK YOUR NEG. BATT. CABLE FOR 10 MINUTES AND IT WILL FIX YOUR PROBLEM DONT GO TO A PARTS STORE AND HAVE THEM HOOK IT UP FOR FREE 90% OF THE TIME IT WILL SHOW THE OXY. SENSOR THEIR IS ALOT OF THINGS THAT CAN CAUSE THIS.