I also used Suzuki khyber on both fuels. But the problem I shoot regarding worse performance on liquid fuel is the bad quality of liquid fuel specially when it is from PSO.
According to my point of view is that the most worse liquid fuel available in Pakistan is from PSO. They make its quality im-pure by mixing some other chemicals and also quantity of the PSO fuel is not proper. Once you fill the tank from PSO liquid fuel, and then run the engine on Gas guel. The PSO liquid fuel can becoming chowks the lines and fuel pump, also it makes the fuel tank rusty enough as it will unable to wash.
If you are getting the problem, the only way is to change your fuel tank and fuel pump both and away from PSO fueling station.
For your kind information that this problem is not only relates with suzuki khyber but it relates with all cars.