I've said this for a long time as well. Most of your 'environmentally friendly' measures implemented on American cars are in fact a burden that reduces your fuel economy. And it is already a federal crime to remove or bypass an emissions control device, even though basically every performance equipped custom vehicle started out by removing most if not all of the emissions devices in the name of performance gains.

And I like so many other technically inclined people have a healthy enough distrust of computing devices to not ever allow a system to tell me what I cannot do. It either does what I tell it to, or it finds itself being reprogrammed to a system that I can be in control of. Its a shame cars are too varied to really allow a GPL drop-in replacement for the typical PCM, but perhaps a platform that could be coupled with DIY hardware using a modular software structure akin to most Linuxes would make it fairly easy for someone with a working knowledge of computers to assemble and program an open source PCM to fit their vehicle. I wouldn't mind trying it myself.

But a lot of cars you can completely redefine their operating behavior as easily as changing a memory cassette in the PCM, with more modern vehicles being dealer-reprogrammable by simply re-flashing the software and tables inside it. I see this as a play by the automakers to guarantee their stranglehold on that capability, so that nobody outside of their authorized dealerships can legally have the tools or software to do modifications on that level, modifications often required by high end performance modding to allow the PCM to work with performance parts.

Far as I know though, the ultimate you can get in fuel economy for a gasoline engine with modern technology is the following. Anything else just burdens the motor or makes you use more fuel than you need. :

Feedback Carburetor- this does have an oxygen sensor and computer, and uses feedback from the oxygen sensor to adjust bypass air. Like so you set the base mixture to suit the engine, and then the bypass trims it richer or leaner as needed to compensate for variations in driving conditions and engine behavior.

"Straight" Gasoline - NONE of that Ethanol crap! I've tested this myself, using '87 octane' gasoline purchased in bulk for a farm tested against '87 octane' pump gasoline from the station downtown that is marked as containing up to 10% ethanol. Well, on a 1.6L carbureted engine, the straight gas was giving me almost 40 MPG, while the E10 was barely making 30 MPG. Now think about this a minute- gas consumed vs mileage travelled, and you suddenly realize that E10 gasoline is causing me to burn more actual gasoline than i would be using on straight gas.

Electronic spark advance - this and the feedback carburetor are among the very few places where the electronics do beat their mechanical counterparts. Simply because the ignition timing can be made far more precise and can respond to changes in operating conditions far more easily than can be done mechanically. Plus the breaker points are a high maintenance area that is often neglected, letting the electronics win in this area eliminates an often neglected maintenance item that has fuel economy penalties for ignoring.

Valve and Bethesda have introduced a program where game mods for Skyrim can be purchased from the Steam Workshop, where traditionally game mods for any game have been available for free.

Needless to say this has kicked over the beehive of a game modding community that has been thriving for the past 10 years without any corporate oversight or financial incentives, and the past few days have been rather drama-packed.

Many mod makers have come right out and said they will not use the new service out of principle, and a lot of the mod makers who have joined the dark side and listed their mods with Steam as buyable packages are facing community blacklisting over how quickly they choose to be greedy and demand money for code that has traditionally been free and is part of a complicated spiderweb of dependancies.

The greatest achievement of PC gaming- a platform that can be easily customized to suit a user's taste has been undone overnight, as suddenly the community spirit that has kept it going all these years is shattered by greed and the cold reality of the for profit mindset.

And seeing all this happening, it is so incredibly tempting to instruct paypal to chargeback every purchase I have made on Steam. Steam would of course ban my account for this action, but I would get my money back and Steam would be one returning customer less.

My opinion of the situation is that game mods are a hobby- something you do because you enjoy it and are having fun with it. The minute you start making a profit from it, its a business interest not a hobby, and you have exposed yourself to all kinds of legal problems between taxes, IP rights, and backlash from people who enjoyed what you made that do not want to pay for what they were getting for free.