why dun you connect your injectors directly and try running the car on Petrol?
This will tell you if there is any issue with emulator which i think there should not be. As emulator is nothing but just a relay type thing that cuts power supply to injectors when you switch to cng.
Just unplug the original wiring plugs of your injectors going into emulator plug and plug them directlly to your injectors, switch to petrol and try your car.
I can suspect this behavior bcoz of advancer if its not a original one that can cause this.
What was the last time you changed your Air Filter/Plugs ?
One more thing did you install a relay for your fuel pump that when you switch to CNG your fuel pump stops working?
Though we do have return system on fuel systems but its better to get this relay installed.