If that was the case, then a full tank of gas for an average sedan would weigh close to a quarter-ton. Guess that the laws of physics (matter can neither be created nor destroyed, etc etc) don't apply to global warming.
Lies are bad enough, but these are STUPID lies. And unfortunately, too many people went to gov't schools, and are too concerned with celebutards like Paris Hilton, to call the liars out.
You are forgetting about the input from the oxygen during combustion.
http://www.epa.gov/otaq/climate/420f05001.htm
As loathe as I am to say it — the “inventor of the internet” may not be too far off on that one.
I think what they do is say that the fuel provides the carbon part, and the air provides the oxygen part. So when one ounce of fuel is burned, it combines with the ambient oxygen to produce 75 million tons of planet killing CO2.