First of all, I'm a big foe of cng in this car. This is a high end vehicle and jugaars like cng kits ruin the overall performance + life of engine in the long run. Get rid of the cng kit asap.
Due to cng, car runs hotter, more wear and tear takes place in your combustion chambers as well as the cooling system and at the cost of what? A few hundred rupees less? I mean come on! Really? Also, cng requires air flow restriction due to which car runs worse on petrol as the air is choked causing lower rpm issues and stalling. Get rid of your cng kit and you'll rediscover the true potential of this vehicle, and you'll like it when you drive it.