Greetings Dillip,
The first thing I would do is check for vacuum line leaks and do a Throttle Body Adaptation.
# Disconnect battery for 30 mins.
# Reconnect
# Turn key to on for 15 secs ( You will hear clicking as the adaptation is going on ).
***Start engine***
If it doesn't improve, check again for vacuum leaks. - If no vacuum leaks can be found. Scan the car with an OBD scanner and check the O2 sensor.
Report back with the results and let me know.
Cheers!!
Moe