One question id like to ask all is:
The spark plug gap of Vitz is 0.8mm (0.04inch), ok ! But if you drive your car on CNG, is it better to reduce the gap or increase the gap ? Does the spark increases if you increase the gap thus increasing in easy starting and smooth idle, greater fuel economy etc etc OR Should u reduce the gap to make the spark more stable and that is good for the car ?
if normally you car setting is for 0.8mm on petrol, would it be good if you reduce the gap or increase the gap if you drive your car both on petrol and cng