Drive around town in "D" or "3" for MGP?

[Astroman]

Originally Posted by arose62

I'm quite impressed by how smart my 2013 Yaris automatic transmission is - if I'm going downhill, and leave my foot really, really lightly on the accelerator, the fuel consumption drops to less than 1.0 l/100km, if I take my foot completely off the accelerator above 70km/h, the consumption drops to 0, and the car gradually slows under engine braking,

What I've recently noticed is that under 70km/h, if I take my foot off the accelerator completely, slight engine braking happens, with low (but not zero) fuel consumption (as if the car knows I want it to keep rolling).

But, if I tap the brake pedal, the fuel consumption drops to 0, and more significant engine braking happens. So, if I'm approaching red lights, I lift off the accelerator, tap the brake, and coast to a stop using zero fuel, whereas if I *don't* tap the brakes, I still coast to a stop, but more gradually, and using (slightly) more fuel.

These behaviours don't seem to be documented anywhere in the owners' manual.

Cheers,
Andrew

It's called DFCO, and I believe it was in my 2007 owners manual.

[David C]

Originally Posted by Astroman

It's called DFCO, and I believe it was in my 2007 owners manual.

Same manual also states to only use 3/2/L for engine braking or for short period of powering the wheels, but not for extended use (aka regular driving). My understanding of the statements of the user manual so far is that 3/2/L gears are there as an option to take advantage of more controlled engine braking and for emergency manual gear selection, in case the transmission goes bad, you can still manage to drive to your destination/safe zone/repair shop with a lower gear that won't strain the damaged drivetrain too much. I don't think as of now that you should select any of the 3/2/L instead of OD for driving, as it would be the equivalent of driving a manual transmission in a single gear with the engine struggling for staying in the ideal RPM range non-stop. That's how I understand it for now.

[kevinj93]

It really depends on what you want. Leaving the transmission in D will allow it to select the most economic gear for the speed you are travelling. Putting it in 3 will lock out the overdrive 4th gear, providing slightly quicker acceleration and more engine braking while using more fuel.

What is more important to you? Performance or economy?