@jjaawwaadd
Please tell us, by this time, what have u already tried? Like checking air filter, CNG Kit, tuning with plugs, tapettes and CNG flow valve adjustment etc? what else do u have in mind? What guesses have the mistris provided?
Have u ever noted the rpm value (on a straight road) at which the gears change? What is the typical value after which the gear is shifted up. If the gears (1,2 n 3) are shifted up very quickly then u may have a pick problem.
I have no experience with EFi so need clues here. BTW, for an expert opinion, I always turn to Waheed Sb; the owner of Capital Autos (on the south facing workshops line just behind Urdu University/ Fire Brigade). He provides the less epxensive solution with explanation if required.