while at it. when do the car consume more fuel while stopping at traffic lights. when on Neutral or Drive.

RPM is slightly high at neutral, but at Drive the RPM slows down but the car groans in pain and vibrates as it struggles to move but brakes zimenyongwo...its on load and thus consumes more power.
So RPM is not the correct measure.

At neutral the engine has to burn certain amount of gas to keep running… it is not in gear thus has to struggle a lot more.
The RPM is direct indication of the gas you are burning – Doesn’t this shows how many times the engine is revolving per minute? The more the RPM, the more the energy used?
You are actually better of engaged in Drive as this way you reduce the wear and tear when moving the stick. If however stopping for more than one minute, you are better of shutting of the engine.

At Neutral the engine struggles to run as compared to while on load???
Only if I were a blonde nurse, but with my heavy technical background, NO please, thank you.

@McReggae why is it normally advisable to leave it on drive? Any link please? My hand is always shifting that thinh to Neutral naturally when in stops!

@Impunity, there is no notable vaporisation in my opinion. Please take note:
• Fuel tanks are located on the sheltered underside of the cars, so no much temperature rise within or in vicinity of the tank. Gasoline evaporates at 350C at atmospheric pressure.
• The fuel tank has air tight lid, so no vapour leaks out of the tank.
• The air in fuel tank is always saturated with gasoline vapour, so there is negligible vaporisation.
If you left your car with half full tank for considerable period of time, how long would it take for all the fuel to vaporise and disappear?