An engine control system for a vehicle includes a timer module, a stochastic pre-ignition (SPI) mitigation module, and a boost control module. The timer module tracks a period of operation of an engine where vacuum within an intake manifold is less than a first predetermined vacuum. The SPI mitigation module generates an SPI signal when the period is greater than a predetermined period and the vacuum is less than a second predetermined vacuum. The second predetermined vacuum is less than the first predetermined vacuum. The boost control module reduces output of a turbocharger in response to the generation of the SPI signal.