Car engine light comes and, sometimes it gets off automatically.

Bikram, the car may seem to be running fine, but check engine lights get turned on for a reason. There are several kinds of errors that will allow the light to go off if they don't occur within a certain number of startup/shutdown cycles, and that sounds like what's happening. You're getting an error that's serious enough to turn on the Malfunction Indicator Light (MIL) AKA the "check engine" light but it appears to be intermittent and goes away long enough to allow the light to reset but then later comes back again.

I don't know where you're located, but here in the US you can take your car to any auto parts store and they will hook their scanner up to your car and read out any Diagnostic Trouble Codes that are present and tell you what they are for free. If that's not an option for you, there are bluetooth OBD-II interfaces available on the internet for just a couple of dollars that can be used with a free app on your phone that can allow you to read out those codes.

Either way you really should find out what's turning that light on to avoid the possibility of long-term damage to your car. It may indeed turn out to be something that isn't serious and can be ignored, but it could also be something that you may need to address so it doesn't cause more serious problems.

So go get those codes; once you have them come on back and add them to your question and we'll see if we can help you figure out what the problem is and what you should do (if anything) about it.