For the abovementioned problem, i went to a 3S dealer, mechanic checked the car and told me that car Emission system and ECU is faulty. he advised to leave the car, they will replace the items and check again in two days. and bill will depend on final check which may be around 20k.
I just came out and went to a roadside mechanic having good reputation. he worked on car and after 15 mins car was fine. he just cleaned pressure switch and reduced the over flow of gas. he even didnot take any charges (may be bcz of my first visit to him). i drove the car for two hour.......... no problem found.
you can imagine the expertise of 3S dealer mechanic and a road side mechanic.