Reduced engine performance: A dirty or clogged air filter can restrict the flow of air to the engine, causing it to work harder than necessary and reducing engine performance, such as reduced power or acceleration.

Decreased fuel efficiency: When the engine is starved of air due to a clogged air filter, it can cause the fuel mixture to be too rich, resulting in decreased fuel efficiency and increased emissions.

Unusual engine sounds: A clogged air filter can cause unusual engine sounds, such as a sucking or wheezing noise, as the engine struggles to breathe.

Dirty air filter: If you inspect the air filter and it appears dirty or clogged with dirt, dust, or debris, it's a clear sign that it needs to be replaced.

Mileage or time: It's generally recommended to replace the air filter every 15,000 to 30,000 miles or every 12 to 24 months, depending on your driving conditions and the type of air filter you use.

If you experience any of these signs, it's important to have your air filter inspected and replaced if necessary to ensure proper engine performance, fuel efficiency, and air quality.