Vehicle Comparison

Yes it does, you put more stress on the engine, imagine pulling a cart pulling over a car. Unless a diesel, they can go out as much as the frame can handle without breaking, and still get good mileage.

yes because your car / truck works harder to move forward or backward, the better your vehicle runs, the more gas it needs to run!

Mary Jo is right!

Do you ... which takes more energy?
Running with a backpack full of rocks or with a backpack full of pens?

the same way with everything else. It uses more energy that comes from fuel!