What do it mean when the RPM moves while in park?

When the RPM (revolutions per minute) moves while a vehicle is in park, it typically indicates that the engine is idling. This can happen due to slight fluctuations in engine performance, which may be caused by factors like fuel mixture adjustments, air intake variations, or a malfunctioning component. However, if the RPM fluctuates excessively or irregularly, it could signal potential issues such as a vacuum leak or problems with the idle air control valve. Regular monitoring can help identify whether it's a normal behavior or a sign of a deeper problem.