MPG Mystery SOLVED!

[otterhere]

"...popping into 3 @ 1100 rpm to maintain DCFO then up into N at stoplights..."

I'm also a good-enough sport to post that I have no idea what you're talking about here.

[Mikeb Yaris]

Originally Posted by otterhere

"...popping into 3 @ 1100 rpm to maintain DCFO then up into N at stoplights..."

I'm also a good-enough sport to post that I have no idea what you're talking about here.

There's a sticky on the mileage thread about it, but here's the short version. The Yaris is programmed to literally shut off the gas to the engine every time you lift off the accelerator above 1100 rpms. This has the effect of engine braking, but more importantly the engine doesn't idle burning fuel when you are decellerating. When the engine speed goes below 1100 rpm, gas is again fed to the engine at idle rate.

SO, if you let off the gas (early) when coming to a stop, allowing the engine to do the braking instead of maintaining a constant speed and hitting the brakes, you will save gas! Also, as you decellerate, if you pop the gear shift over into 3 when the rpms hit 1100, you will maintain this effect for a longer period - right up to the point where you HAVE to put the brakes on to actually stop.

When at a stop light in D, the engine is trying to move your car and your foot on the brake prevents it. This puts a load on the engine causing it to burn more fuel than simply at idle. So, you pop the shifter into N and this releases the load on the engine and you'll burn less fuel at the stop lights.

So, you see, when I'm driving in town I cycle from D when maintaining speed, lift off the gas early when I see a light ahead, pop it into 3 to extend the fuel savings and increase/continue engine braking, pop into N when I've come to a stop and then back down into D when the light changes.

I'm currently averaging just over 41 mpg with my lowest tank at 38. This and running max tire inflation are the things I credit my success to.