99 baleno is exellent on cng if you take care of the following.
use normal plugs of Denso or NGK. ( dont try fancy platinum or irridium plugs).
change air filter frequently.
throttle body cleaning after some time from good mechanic.
use 1 good cng station always for filling cng.
never wash you engine bay while servicing.
use Landi Renzo or some good kit from a reputed mechanic and install igood mmulator and advancer.
drive your car on petrol 3-4 km before turning on cng.
always start your car on petrol.
use 20w50 grade engine oil of good company like Mobil, petromin, liquimoly
or use castrol magnetic gtx.