Manual or Auto?

[greenfoam]

But it takes the engine power to move the cogs around : ) and the torque converter is not a direct conection so you loose some power there while it's sludging around

 

[chevy_big_block_bro]

yea, there is a little economy lost with the engine having to spin the oil filled torque convertor.
if you read you car manual in the glove box, you will find that the manual uses less fuel over the 100km, its not much but it does count