|MadSci Network: Engineering|
Yes, a gasoline engine can definitely be converted to run on methane. The more common term for methane is natural gas. And natural gas is used all over the world to power cars, heat houses, cook food, etc.
The term you'll hear most often when refering to vehicles converted to run on methane is CNG for Compressed Natural Gas. There are many commercially available CNG vehicles on the market. There are also companies who sell converted gasoline engines, or will convert your engine for you.
Here are a few links to learn more about methane and CNG vehicles:
Your Mad Scientist,
Try the links in the MadSci Library for more information on Engineering.