[Banana Jack]

A second ago i became curious about the difference between auto and manuals while coasting in gear. i drive an automatic, and it smoothly decelerates when i let off the gas. i drive a stick, and it slows down much faster, with a slight jerk right after i let off the accelerator. which makes me think i get worse gas mileage in a stick, even though sticks almost always get better mileage(though the difference has become quite small with newer cars)
so i googled it.
"The fluid coupling between engine and transmission is almost a one way street, transferring about 90% of the power from the engine to transmission, but transferring very little the other way. The clutch locks the engine to transmission with no losses as there are in the fluid coupling, so energy is transferred either way equally. The fluid coupling works much like the ratchet mechanism in a bicycle that transfers power to the wheel when you apply pressure to the pedals, but otherwise the back wheel free-wheels and clicks allowing you to freely turn the pedals backwards while coasting along. The person above who talks about gearing is not quite correct. In a 4 or 5 speed manual transmission, the gear ratios are very close to those in a similar automatic with 4 or 5 speeds. Engine braking works in a manual only because the power coming from the wheels gets back to the engine. In an automatic, virtually no power gets to the engine from the wheels because of the slippage in the fluid coupling."
so the inefficiency of the fluid coupling is the reason autos get worse ratings, it looks like.
but with this in mind, does deceleration fuel cutoff work in automatics? it doesn't sound like it should... if the wheels aren't connected to the engine then they can't force it to turn and let the injectors shut down...