What is indicated by too little fuel in the air/fuel mixture?

A lean air/fuel mixture occurs when there is insufficient fuel in relation to the amount of air present. This imbalance means that there isn't enough fuel to achieve optimal combustion, resulting in a mixture that has a higher ratio of air to fuel. In engines, a lean mixture can lead to higher combustion temperatures and inefficiencies, potentially causing engine knocking and increased wear over time.

The balanced air/fuel mixture would involve an equal ratio of air and fuel, which allows for efficient combustion without the risks associated with running too lean or too rich. A rich air/fuel mixture, conversely, indicates an excess of fuel compared to air, which can also lead to problems like reduced efficiency and increased emissions. Corroded mixture is not a standard term used in this context, making it irrelevant when discussing the characteristics of air/fuel mixtures. Thus, too little fuel in the mix is clearly characterized as a lean mixture.