Without reading any of these responses I will say that I tested this out the other day.

I filled up my tank and then reset the onboard computer to check my MPG.

It is only 1/2 a mile from the Shell to my house so while driving home I blipped the throttle when downshifting and braking and I watched as the MPG numbers went WAY down. It was 19.2 and dropped to 15.4 by the time I made my final turn into my garage.

When the RPMs go up the MPG goes down.

As a general rule, I've been following the "coast to a stop" philosophy. It seems to make much more sense to me to have the engine at idle as I coast from say 30-40 mph than to have the idle at at any other RPM. I also think its fun to see how well I can use my momentum to use the brakes as little as possible to come to a stop. This requires you to look far ahead as possible which is a trait you need in motorsports so its kind of putting theory into practice.

OK now you open up a whole new can of worms...

Crude Oil is traded as a commodity and therein lies the problem. As a commodity, it's price is based primarily on Investor Confidence - confidence that an Investor can buy it and then later sell it at a profit !

Geo-political environment and events play a much greater role in establishing this Investor Confidence than do Supply and Demand (though these too play a lesser role).

Having it commodity-based allows for much greater manipulation of the price than if it were simply a raw material bought and sold as such. There is no way of setting a price of how much it should cost us... only what we're both willing and able to pay.

Indeed, There is no SHOULD, there is only the point at which supply and demand meet.

coasting in neutral, instead of in gear... we're talking pennies here.

my take on it, leave it in gear, why, because if you don't, its DANGERIOUS! leave it in gear. when you are in neutral, you loose out on engine braking should you need to panic stop, should you need to evade something, you now have to put it back into gear, then accel out from whatever it was that you were about to hit.

FWIW, when I took my driving test years ago, the only point deduction that I got, and I almost failed because of it... I put the car in neutral too far before the stop sign, (about 100') I was already under 10mph. And some of the people here are talking about coasting it at 40mph? wow! i'm guessing you're coasting for a several hundred yards? are you at least leaving one hand on the shifter, so that you can get it back into gear quickly?

reasons I didn't buy a Porsche:

- to save on gas, even though this is my most fuel efficient car right now.
- to save on tires and purchase all-season touring tires

Good point.

If you want your paint to last longer, don't wash it.

If you want your car to last longer, don't drive it.

If you want fuel economy, find an old Geo Metro.

If you want to have fun, step on all the pedals all you want.