No fuel and no spark. Think along the lines of pop starting a car, pushing the car, pop the clutch, causing the motor to physically turn over, u then initiate spark and fuel and voila, it starts running.

If u take an engine, and hand crank it through its revolutions, it becomes a big air pump, u can turn the motor all u want by hand, and itll suck air all day, never using spark or gas.

Im not sure what other way to relate this, hopefully someone can come up w something better.

Actually, right after you start your car neither the engine nor the catalyst (in the cat converter) is at operating temperature so NO, DFCO would not come into play right after starting your car. DFCO needs everything to be at operating temp. Once your engine drops below a certain RPM (I don't know what is on the FRS but typically it's something like 1000-2000 rpms) then the injectors start firing again, even if the car is still decelerating due to how close the rev range is to idle.

And actually I'm not necessarily saying it, your OBDII computer is saying it. In some cars the ignition system does turn off too but that's not common.

Why is it that you think an engine can't spin unless it's combusting something? My mind is open, please explain.

Also, I have not confirmed that the Injection system in the Twins runs DFCO but considering it's OBDII, the chances are very likely.

My yaris has this system, don't see why the frs/brz wouldn't.. so long as you don't touch gas or clutch after decelerating for 1-2 seconds it will shut off fuel or spark not sure which, mebbe both... until rpm gets around 1400 ish I believe.

The best I've gotten was going to Vegas then stopping in Baker in 1 tank. Was about 370.3 miles or so. According to the car I was geting about 37MPG. I think actual was about 35 though. I believe it still had a couple gallons left when I filled it too.

The thing to remember is drag increases exponentially with speed. The power needed to accelerate and hold the car from 60 to 70 is far greater than what's required from 50 to 60.

Obviously different things can ameliorate that general principle. If you can maintain 70 in traffic, you'll probably still get great mileage thanks to the drafting. But without someone clearing a path in front of you, you're better off keeping it below sixty.