The O2 sensor reads exhaust gases. Intake air is sensed by the Mass Air Flow (MAF) sensor. More air won't flow unless you step on it more. I suspect that your loss was from not being able to resist testing it out every time you step on the gas.

exactly, and if you can't buy a new vehicle, make your existing one more efficient ( I believe is the point....)

I didn't see new fuel injectors on the list...one of my injectors stopped firing so I figured I'd get a new set (instead of just one). I got Ford Racing injectors for 1/4 the price of OEM. they have better controll and a much better spray pattern. They gave me significantly better milage and power, the added power helped my use less loud pedal, which gave better milage again. I havn't kept accurate records so I can't say how much, but it was noticable (over a year ago..)

Taxes on Fuel
 

I agree with Nerys

Further taxes on oil companies misses the point. Consumers will just have to pay for it.

In the UK the taxes are what make the fuel prices so high.

Currently the Treasury rakes in ?500 Million PER MONTH in taxes on fuel!

Crazy!

David
https://www.runyourcarcheaper.blogspot.com

Adjust idle speed to lowest possible RPM.

On fuel injected cars learn to use downshifting (manual tranny) to engage fuel shutoff with your foot off the gas pedal. Same results as turning engine off as long as you are over 1000 RPM.

regards
gary

Saving gas at the pump station
 

All the tips and suggestions have been on the consumption side, e.g, change driving habits, modify cars, etc.
How about getting more buck for your gallon at the pump station?
I got some tips from a friend at www.reddiv.com/FillingUpPetrol.pdf who suggested pumping your gas early in the morning. As fuel is denser when temperature is cooler, you get more gas per gallon when you pump your gas in the morning. There are more useful tips from the article. Sounds logical to me.

That's a great one, and I do it as much as possible. It's called DFCO (Deceleration Fuel Cut Off). One gotcha on it: Not every fuel injected car behaves the same. Some work as Gary described, others only do it after extended periods of engine braking. Some require speed to be above a certain threshold when you begin. If you try for DFCO but it doesn't happen you're likely to use more fuel, not less (as I directly measured in two vehicles).

The contents of that PDF are the same as the chain email that goes around, and in my opinion are mostly either bunk or have such a small effect as to not matter. More importantly, the PDF has an added part that says this:
"AND IF YOU REALLY WANT TO STRETCH YOUR PETROL DOLLARS, TRY
THIS METHOD. IT INCREASED MY MILEAGE BY ALMOST 69%!
CLICK HERE FOR MORE INFO"
...and it links to "reddiv.com/cgi-bin/ct/click.cgi?id=10" (removed http and www so it won't be automatically linkified) which is a redirect and is most likely either a miracle snake oil sales page or made to attack vulnerabilities in browsers.

Thank you, new member, but we've already seen those tips.

You may have seen the tips, but others may have not.
I'm no scientist, but I've learned elementary science in school to know that this guy is not talking nonsense.
Take it with a grain of salt if you like, just don't dismiss anything without even bothering to try it out.

You should add Rain-X to lower the power you use from the alternator. I know it won't save much, but it's one of the easiest things to do, and if you decided to take off the wipers it could save a lot more.

removing the alternator altogether would be better, but is there some kind of clutch that can disengage the alternator when you don't need it?

Well, the alternator is regulated so that when it doesn't need to provide power to a full battery, it doesn't.