Check this out, I happened across this little product:
Here

Seems a bit suspicious, "When plugged into the cigarette power port of a vehicle, the Fuel Doctor FD-47 Fuel Efficiency Booster helps to clean and condition the electricity in the system"

Not sure how that would work...cleaning electricity? I'd give it a whirl just for the hell of it, but then I'd just feel like a chump when it inevitably amounts to a placebo at best.

I don't believe it. Doesn't make sense.

outside of better sheilding, cableing and termination i dont see how this device that offers no explanation to its functioning would make enough difference to net a 15%-25% impact in fuel econ.

even with all that stuff i dont think those numbers would be possible

If it charged my ipod i'de be a little more intrested

Clean and condition the electricity? I'll do that for you for $20! Just let me have your car for a while

consumer reports apparently could not measure any fuel econ. difference with or without the device

http://abclocal.go.com/kgo/story?section=n...&id=7886474

I kinda feel bad for the people that fall for this crap...

... then again; at the same time - they kind of deserve it.

http://autos.yahoo.com/news/fuel-saving-de...s-debunked.html

here are several tested results for products of the fuel saving nature. That exact product is on there, and is one of the few that showed any improvement (a few actually showed a decrease in mpg).

LMFAO, the bottom one on this link claims that fuel molecules cluster in your tank over time and the molecules in the middle of the cluster cannot be exposed to oxygen for proper combustion. First off, the molecules do not "cluster" as stated. Secondly, if they did, the only way the ones in the middle wouldnt be exposed to oxgen would be if the fuel was being ignited inside of the tank. Not to mention the fact that fuel lines, pumps, and just adding fuel to the tank mixes everything well.

i got a can of shark pee that cures cancer if you believe in this

There's not a lot that Shark Pee can't cure in this world...

It needs to be said that fuel efficiency and fuel economy are not the same. Our 5S's and 7A's are very economical- they get good gas mileage- but are they efficient? Do they burn 100% of the fuel that goes into the combustion chamber? Do they convert every single drop into power? There's a reason truck commercials can get away with saying they have the most fuel efficient truck without getting sued. You can get 3 miles to the gallon but as long as none of the fuel is wasted, you get 3 mpg efficiently.

I'm too lazy to click the link right now, but I already see that this product states nothing about economy, only efficiency, and who really has the tools laying around to test efficiency? Regardless of their claims, I'd buy Smaay's shark pee before buying anything that plugs into my cigarette lighter and claims to change my vehicle. Think about it- your cig outlet only sends electricity- it isn't designed to get any back. And if it did, it isnt hooked up to the ECU or anything that could affect the motor's mechanical operation. This product is a waste of money.

Yes, the consensus is as I would expect from an intelligent community. This thing looks like a joke the more I research it. I love that when they opened it up, it was just a circuit board for the LEDs LMAO. This is why customer reviews, for all their biases, are one of the greatest implementations in online shopping.
Also, that's a very interesting response richee3, I had never thought of it that way.

Do we have a thread listing legitimate mods for fuel economy improvements? That I would be interested in.

ahahahahahahhahahahahahahahahahahahahhahaha

See the aerodynamic panels thread in exterior.

Lay off the gas pedal. See also ecomodder.com