19.64 - http://www.patagoniaalliance.org/wp-content/uploads/2014/08/...
20 - https://climatekids.nasa.gov/review/carbon/gasoline.html
20 - https://www.fueleconomy.gov/feg/contentincludes/co2_inc.htm
19.6 (converted from grams) - https://www.epa.gov/energy/greenhouse-gases-equivalencies-ca...
“Just over 19” - https://epicenergyblog.com/2013/05/24/how-many-pounds-of-car...
The next hit isn’t about CO2 from burning Gas, but about the upstream emissions that go into producing gasoline, which it pegs at 3.3 to 6.7 per gallon - https://www.sierraclub.org/sierra/ask-mr-green/hey-mr-green-...
What sort of estimates are you getting?
Yes, “gasoline” is a family of related fuels of different densities and compositions, and it will also vary based on assumptions about how it is burned. Incomplete combustion will result in more “dirty” pollution and less CO2.