Have you asked yourself if using synthetic oil will help give you better fuel economy/gas mileage? The simple answer is, it most most certainly will.
This is one reason that Amsoil ONLY manufactures synthetic oil.
Engine produce a LOT of heat. Think about the number of moving parts within your engine that require oil for the express purpose of lubrication. Every wear point is a friction point and friction robs your engine of maximum power and efficiency. If you could eliminate or minimize the friction at all of those points, your vehicle would be MUCH for efficient. A more efficient vehicle doesn’t take as much power, or in this case fuel, to move so your fuel economy/gas mileage is significantly improved.
Don’t take Amsoil’s word for it, do the research yourself.