If you are referring to turf, or what some people call peat, then the answer is a bog.
fossil fuel and shamrocks
Comparisons on hybrids and fuel efficiencies can be found in many places; ConsumerReports.com is a great place because you can easily compare all makes and models in one place. The Consumer Reports can also be acquired at most local libraries or bookstores for any given year.
Information about solid fuel can be found on the website WHO household energy database. Information about solid fuel can also be found on Wikipedia, Solid Fuel UK and Zen Stoves.
waergh
in the fuel tank
The fuel filter is found inside of the fuel tank. It's hard to reach it. On earlier subarus, the fuel filter was found in front of the brake master cylinder.
in the fuel tank only $130 at parts store if your doin it yourself will take part of day, but $700 to $900 for a garage to do it for you i got lucky and found one place for $320
The fuel gauge sending unit would be found inside the fuel tank.
gasoline
The Diesel Index indicates the ignition quality of the fuel. It is found to correlate, approximately, to the cetane number of commercial fuels. It is obtained by the following equation
the pump is found in the fuel tank
Drop the fuel tank. There are two straps holding the fuel tank in place, support the tank, disconnect the straps, lower the fuel pump enough to unplug the wires, pull the fuel line connections, then get the tank to a place where you can work comfortably and dig all of the tar and mud from around the top and remove the fuel pump. Put the new one back and reverse the process. I found it was a little easier and quicker if you can take the bed off, (so you wont have to lower the tank), but it does depend a lot on the truck and the situation...