You answered ur question ur self. Liana on CNG is a flop. Petrol Liana owners are happy, and secondly do u find any reason for Paksuzuki offering CNG in Liana and not in Swift.
main reason being the waste-spark system is a flop on CNG in Pakistan
Waste-spark system cars (Baleno, Liana, Santro, Lancer 1.3, Swift)
@all, dont come up saying meri falani gari theek chal rae hai, its coz if these cars are runing gud on cng its the best thing but if it gets messed up its a missery
Secondly by installing a after market cng in a brand new car u void the warranty so i dont c any point in doing so. atleast u shud drive it without any modifications or harmful alterations within the warranty period.