Well i followed your advice and tried to follow the steps you mentioned. But couldn't find any leak, the smell comes for a moment sometimes and it goes away. Not getting continuous smell. At one instance when i felt the smell i immediately stopped my car and opened the bonnet to find the leak, but the engine was dry, even the petrol pipes were dry. Also today i faced jerking issue on CNG in the morning on AC on. When i tried to accelerate and went above 40-50 felt a jerked. I turned off the ac and the drive became smooth. After sometime when i turned of the AC again and accelerated, the jerking didn't occur. Anyone here ever faced the same issue?