I know, you are thinking you can't power your vehicle with water, however it's absolutely true.
There is a inexpensive way to convert water to hydrogen and use to supplement the gas and make your car 20 to 50% more fuel efficient.
It's called HHO or Browns Gas.

The relatively simple device uses a little electricity out of your car's battery, to separate water into a gas called HHO (2 parts Hydrogen + 1 Oxygen). HHO, also called Hydroxy , burns beautifully and provides 3 times the power of gasoline. HHO is a fast growing trend for boosting performance and MPG / KM/L

I am sure you are curious perhaps even suspicious as to why you haven't heard about this from big business. Reason is actually quite simple. This technology is in the public domain and open source so anyone is free to replicate it and it can't be patented. Consequently big business can't profit from this. You will be hearing about it only from the grassroots level, small business that don't have shareholders. Did you know publicly traded companies have a legal obligation to earn a profit for their shareholders?

There are plans widely available on the net to construct this device. For your convenience I am providing a list of key words so that you can do your own Google search and see for yourself this is indeed real: "browns gas, cars run on water, car that runs on water, easywatercar.com, HHO, hydroxy fuel cell, improve gas mileage, map sensor enhancer, pcv enhancer, run your car on water".

Easy to install & maintain.Good for carb/fuel injection,gas/diesel.Old/new cars and trucks big and small.

Widespread development and experimentation by numerous back yard engineers has proven this is feasible. With this method you can run your traditional automobiles partially on water (that's a "Water Hybrid") with little or no modifications.
* You should be able to increase your gas efficiency by 20 to 50% or more on some vehicles.
* You can drastically cut down emissions and help reduce Global Warming.
* You can improve efficient burning of fuel and consequently lessen wear and tear, engine clatter, high temperature in the engine, carbon deposits, etc.

You see, you have just hit upon some unique information. (This may not be unique for much longer) You can find people selling kits and doing installations, however they are not in the yellow pages as yet.

It would seem the most complex part of the system is getting it to work with the computer on all cars since 1996. When the oxygen sensor senses more oxygen it automatically sends in more gas lowering your fuel efficiency instead of increasing it. Not to worry though you can purchase or even build your own MAP Sensor which will allow you to adjust the mixture of gas and air.

You can obtain complete informational products or ebooks, packed with guidelines and suggestions. There are discussion groups with 1000's of members helping each other with any mechanical, electrical or tuning trouble. Please keep in mind people will always have different opinions and you must use your own judgment when listening to what they have to say. If you are offered a conversion kit or installation be certain they are willing to provide you with after sale service, returns warranty etc.