Shayan hope your problem would be solved by now. Your assumption seems to be quite convincing. When the car is working well on CNG and hesitating on petrol, there is a sound probability that you have clogged fuel injectors. Every time we turn off our engine, the last drop of petrol evaporates on the pintle of the fuel injector and leaves behind deposits and varnish. Heat in the chamber bakes the fuel residues and makes it stubborn to remove. This gunk collects on the pintle, and over time it results in injector clogging and leaking. The pintle caps are constantly exposed to fuel evaporation which leaves behind a powdery residue and affects the spray pattern. Usage of fuel additives for cleaning your fuel injectors is hotchpotch solution. It passes through the injector for a short time and makes little cleaning but on the other hand it is harmful for the fuel filters and engine itself. Therefore it is recommended to change engine oil after usage of fuel additives.
I provide off vehicle fuel injector servicing on the same technology which is used internationally. The injectors are electronically tested, flow volume and spray patterns are analyzed and later serviced with the acoustic technology. The solution developed for cleaning is aqueous and is higher than pH 7 level therefore it does not cause any harm to the injector. The injectors are checked again for flow volume and spray patterns after servicing and mounted back to the vehicle. I welcome your enquiries