An idle control system for a vehicle comprises an actuator control module, a torque determination module, a deviation analysis module, and an idle speed reduction module. The actuator control module regulates an engine speed based on a desired idle speed when an engine idle mode is enabled. The torque determination module determines actual torques for a cylinder of an engine while the engine idle mode is enabled. The deviation analysis module determines a standard deviation based on more than one of the actual torques while the engine idle mode is enabled. The idle speed reduction module determines an idle speed reduction based on the standard deviation and decreases the desired idle speed based on the idle speed reduction.