Why does car make a humming or hissing sound under hood when you press the gas pedal?

A humming or hissing sound under the hood when you press the gas pedal can be caused by several factors. It may indicate an issue with the air intake system, such as a vacuum leak or a malfunctioning air filter, which can create abnormal air flow sounds. Additionally, it could be related to the fuel system or exhaust components, such as a failing fuel pump or a leak in the exhaust system. It's advisable to have a mechanic inspect the vehicle to identify the exact cause.