What do you understand by rarefied gas?

i don''t know too

by reading the values

I Think you have other problems. Change the fuel filter and if that doesn't do it take it to a garage.You purchase a gasoline can and a funnel. Fill the gasoline can with fuel from your local...

If you mean a residential gas fireplace, it would burn natural gas, which is mostly methane (CH4).

They buy their fuel from U.S. refineries. They have no control over where the refineries purchase the crude oil that they ultimately sell as refined gasoline to the distributors.