First check your cold starting system
What is your gear box oil? is it EP90??? please never put EP90 for synchromesh gear box. Remove your gear box oil and flush with diesel. Then put GL4 or Thuban (caltex= easy shift or manual trasmission oil) or SAE 80 oil
it is ok but not to forget to keep your eye on temp gauge, bcoz AC compressor and AC condensor getting heat coz there no ventilation. About talking fuel consumption
engine starting> idling speed (firing interval is too long)>high speed cruising>low speed cruising