What is a common effect of a restricted air intake in an engine?

A common effect of a restricted air intake in an engine is the production of black smoke from the exhaust. This occurs because the engine is unable to draw in sufficient air to mix with the fuel during combustion. When there is an inadequate air-fuel mixture, the combustion process becomes incomplete, leading to excess fuel being expelled in the exhaust, which manifests as black smoke. This is a clear indication of poor combustion efficiency and highlights how critical the air intake is to the overall performance of the engine.

In contrast, while excessive engine temperature, increased oil consumption, and low engine power might also result from various issues in an engine, they are not direct or exclusive consequences of restricted air intake. Excessive engine temperature could be caused by other factors such as coolant issues or a failing radiator. Increased oil consumption is more often related to problems like worn piston rings or seals. Low engine power can occur for a multitude of reasons, including fuel starvation or ignition problems, and is not solely tied to air intake restrictions.