Originally Posted by senseiturtle

Fuel economy is not solely RPM based. In fact, a motor is MOST EFFICIENT in producing power from fuel when running at full throttle, at very high RPM. Though, this doesn't translate into good "distance per gallon."

RPM is a factor, but not the sole factor. When cruising at 70mph on the interstate, you're turning over 3000 rpms... yet, you still get ~30mpg! If it were solely rpms, then this real-world observation wouldn't make sense.

In fact, get a Scangauge, and cruise on the interstate at the top of 3rd gear. Set the cruise control, but of course don't do it for long. You'll notice a reduced number, but still over 20mpg.

Your ACTUAL enemies for good MPG are:

1) Acceleration habits.
2) Weight (specifically, engine load).
3) Terrain (as it influences apparent weight of vehicle).
4) Displacement.
5) Adjusted displacement (if turbo/supercharged).
6) Tuning parameters.
7) Wind resistance, in combination with drivetrain resistance.

Now, a little analysis of each one. Let's knock out the ones that you can't control first.

3) You can't control terrain for your daily commute.
4) You cannot change the physical displacement of your motor.
5) Most of us aren't turbo, and those of us who do go turbo, don't care about MPG for obvious reasons.
6) Unless you're 100% managed by a standalone that completely bypasses/overrides ECU... this isn't you either.
7) Outside of adding tire air pressure and driving slower to reduce wind, it's impractical to alter resistances.

So you're down to:

1) Acceleration habits.
2) Weight.
3) Tire pressure, and drive slower to reduce wind resist.

Changing your gears --- won't help enough to justify the project and expense.

---------------------------

1) Don't brake, conserve momentum as much as possible. Accelerate AS SLOW AS TOLERABLE.
2) Carry as little weight as possible.
3) +5lbs of tire pressure. Go 65 instead of 70. Get smaller, lighter rims. Smaller, harder tires, with more pressure. etc.

There are some other tricks that hypermilers do... such as engine braking, since this actually cuts all fuel to the cylinders, rather than a small amount during idle. Not sure if it's worth wear/tear, and it may be make/model specific.

For the most part, don't drive stupid, and enjoy your tC.