What causes loud knocking noise from Kia Sedona engine but goes away at higher revs?

A loud knocking noise from a Kia Sedona engine that diminishes at higher revs could be caused by several factors, including loose or worn engine components, such as a failing timing chain or belt, or issues with the oil supply, like low oil levels or dirty oil affecting lubrication. It may also be related to fuel knocking or detonation due to improper fuel octane. If the noise persists or worsens, it's essential to have a mechanic inspect the vehicle to prevent potential engine damage.