OBD GPS Logger [http://icculus.org/obdgpslogger] was used to log a car journey and export this kml file

RPM and Position
Height indicates engine revs

Trip #1

chart

Trip #2

Trip #3

MPG, Speed and Position
Height indicates speed, color indicates mpg [green == better]

Gear and Position
Height indicates ratio between rpm and speed. While you're in gear, a line should be flat