I can also tech you to tune this vehicle on CNG, that’s not a rocket science.
For petrol:
Plugs cleanup, gap setting, clean air filter and Throttle body cleaning. Nothing much other then this.
On CNG:
CNG Injectors cleanup, Throttle body cleaning, Plugs cleanup and proper gap setting upto 0.9mm, CNG filter replacement after every 40,000 km. look for possible dirty fuses contacts and CNG cylinder cleanup after every 2-3 years and if you can do it then clean the Reducer as well, once in every 50,000-60000k km.