An engine warning light coming on or a check engine light coming on could mean something simple is wrong with the engine and then again it can mean something serious is going on with the engine.
When your engine warning light is coming on it's coming on to alert you to something going on with the engine.
It could be as simple as bad spark plugs, bad spark plug wires, bad ignition coils, bad ignition module, low fuel pressure or even more simpler as in your fuel cap could be lose or not sealing properly.
First thing I would check is to make sure your fuel cap is secure and not lose or faulty.
That is if your car has a fuel cap as some newer vehicles do not contain a fuel cap.
You can take your vehicle to Autozone or Oreilly Auto to have them check why your check engine light or engine warning light is coming on and they will test it for free.
If it's more serious then it could be something internal with the engine such as low engine compression, or engine knock but you'd hear the engine knock.
Either way I would recommend getting the engine warning light tested to see why it's coming on and fix the problem.
Sometimes the engine warning light goes out on it's own and other times it needs to be turned off with a code reading tool.