My Car Vitz have vibration issue on low speed or RPM on brake operation with or without AC so i assume its may be from fuel but I am using 50:50 HOBC and Mix petrol what i realize when scanning ECU the RPM fluctuate to lower than 700 RPM. In 2nd gen vitz IDLE RPM should be 700 or above. I found this information on my car Bonnet. You already mentioned some of the area that caused vibration. I want to know more about this point you mentioned in above post.
RPM setting on Idling
Is it possible we can adjust idle RPM if yes on which software? how can we do that?