I've had two toyota pickups w/ 2.4 l engines, one a 1987 carb engine, and
one 1997 fuel injected engine. I found that the carb model got better
mileage. I have been told that the technique to use is to pretend there is
an egg between your foot and the gas pedal and try to hold the egg there
without breaking it.

This technique seems to work well with the carb model but not the fuel
injected model. The fuel injected model seems to get the same mileage within
reasonable limits no matter how I drive it. I have found that short shifting
helps the mileage on the injected model.

My thought on this are: The carb model meters fuel based on engine vacuum,
ie; load. Therefore I can understand why it responds to a lighter foot on
the pedal.

The fuel injected model meters fuel based on the amount of air through the
intake, therefore even at light load conditions, at higher rpm there is more
air going thru the throttle body therefore more fuel is metered.

I would like to hear the experiences of others as to how they drive to
extract the best possible mileage.

"Marty" <caseype (AT) earthlink (DOT) net> wrote

Doesn't matter. The engine is generally run at the stoichiometric air-fuel
ratio, something like 14:1. Doesn't matter if it's a carb or FI. Either
way, too lean and you stall, too rich and you get a lot of smoke. A very
well-tuned carb might return comparable mileage when fully warmed, a FI
engine would generally deliver better mileage if you consider all driving
conditions as it's more tuneable. You poor fuel mileage is due to something
other than FI I would think.

Cheers,

Scott..

In article <eZhlc.3754$V97.3667 (AT) newsread1 (DOT) news.pas.earthlink.net>,
caseype (AT) earthlink (DOT) net says...
The most important factors are how much energy you waste by going fast or by
stepping on the brake.

Unless you drive a hybrid with regenerative braking, every time you step on the
brake you are wasting the inertia of the car. It is as if you took the same amount
of gasoliine needed to get to that speed, and used it to light a torch under your
brakes. Thus, one component of optimum fuel efficiency would be to drive such that
you don't have to use the brakes too much. A heavy car stores more energy at a
given speed than a light one, so this factor is especially important with heavy
vehicles.

When you drive fast, some of the fuel energy is wasted moving the air around the
car and heating it up. This effect gets worse the faster you go, so the energy
spent on wind resistance at 80 MPH may be 3-4 times as much as at 40 MPH. If your
car does not have a low coefficient of drag (aerodynamic), then you would want to
control your speed as much as you can. I think that pretty much all cars, even the
most areodynamic ones, would get worse mileage at a constant 65MPH than at a
constant 55MPH.

How you accelerate, fast or slow, is not as much a factor and only lasts for a
short while anyway.

Marty wrote:
By 1987, your truck should have a feedback fuel system managing the
carburetor mixture. So whatever you do with the throttle, an ECU
ensures the air/fuel mixture is optimized as quickly as possible.
Take a look on your exhaust manifold or the exhaust header pipe for
an Oxygen Sensor. Other things like cam shaft profile and timing,
ignition timing, EGR levels, and gearing all must be considered in
the comparison you've presented.
--

- Philip @ Maximum Torque RPM

In short: coast as much as possible, and reduce your maximum speed.