For Honda City owners who might have experienced bad fuel consumption after installing grounding cables onto the car, taking out your car battery for extended periods of time or anything that might have caused the ECU memory to be reset, go back to your Honda service center to rectify the problem.
This is an issue with the CVT gearbox, where there is a start-up clutch activated via hydraulics when you shift into D from N or P gear positions. When the ECU memory is reset, start-up clutch calibration information is lost and sometimes the ECU detects the clutch full engage/release positions wrongly.
Please refer to this thread on Temple of VTEC Asia forum where a very experienced Honda driver WongKN has posted his thoughts on the matter.
I believe this information should also apply to Honda Jazz drivers as the engine and CVT gearbox is the same.