Here is a article that was e-mailed to me:
the last several weeks many of you have emailed me about techniques
and tips to improve gas mileage. Let's make that this week's topic.
Today's cars and trucks are designed to run with the best mileage, power
and emissions possible, and they do a great job of it. So what can you
do to save at the pumps in your vehicle? Here are some tips.
Buy cheap. Don't pay for "premium" unless your manual recommends it.
Unless you're driving a Corvette or turbo-charged car, the odds that you
need premium are slim-to-none. There's no upside to using higher octane
fuel than necessary. Some name-brand fuels may have better additive
packages than no-name fuels. I don't have any hard evidence one way or
another that it would affect mileage or maintenance, but it is worth
noting.
Check your tires. Both for safety and economy. Keep a tire gauge in your
car and check your tires every time you fill your tank. Use the pressure
recommended for your car (look in the door jamb or under the truck lid
for the manufacturer's recommendations).
Put your car on a diet. Don't keep extra weight in your vehicle.
Keep in tune. Keep up with the recommended replacement schedule for
ignition components such as spark plugs. Keep a clean air filter. Be
sure your fuel injectors are clean (an occasional bottle of injector
cleaner additive isn't a bad idea). Use AutoTap or another scantool to
be sure that you're not having problems with misfire.
Don't use the brakes! Don't take this one too literally, but there is
nothing you can do that hurts your mileage more than pushing the brake
pedal. Every time you push the accelerator you've made an investment in
your car's momentum. Every time you brake you throw that energy away.
(This and the next tip are worth 10 times all the rest!)
Watch your top speed. At highway speeds, small increases in speed
require much larger increases in power. Slowing down a few mph on the
highway will save you dollars. If you own AutoTap, try monitoring the
"Percent Load" parameter at a couple different speeds on a flat highway
and you'll see what I mean!
What about all the fuel-saving devices that are marketed so aggressively
today? Total waste of money on fuel injected cars and trucks. That
certainly doesn't prevent them from selling huge quantities of these
high profit-margin products. But, don't mistake profitability and
celebrity endorsements for science! The fact that we'd all like to
believe that they work doesn't change the rules of physics.
So how do they get away with their outrageous claims and "proven"
results? One answer is the use of weasel-words. Remember "Up to 10%
Savings" includes the number zero!
Another answer can be revealed with AutoTap. Some of these devices add
an airflow obstruction in the intake. While I haven't tested any of
these devices, I have seen test results on another engine modification
that performs a similar function. The results? The intake air becomes
turbulent as it passes through the Mass Air Flow (MAF) sensor. When the
air flow is turbulent the sensor gets confused. On some vehicles, this
causes the engine to run temporarily lean. This could improve mileage
(at the expense of emissions, durability or power). However, if you
remember our previous emails about oxygen sensors, you'll recall that
these sensors will detect the lean condition, then "learn" how to
correct it. What does this mean in real life? For a short time, there
could be a small improvement (and this would be a good time to make
measurements for advertising claims!). But, give it a week or two and
the computer will tune the fuel mixture back to where it belongs, and
any gains will disappear. Monitoring the long term fuel trim parameters
with AutoTap reveals this behavior.
So don't help fuel that snake-oil industry. Use some of the practical
tips in this week's email to improve your economy. Will you see huge
improvements? Not likely. But small improvements can add up!
Happy Repairs,
Mike Fahrion
www.autotap.com <
http://www.autotap.com