1. An engine control system for a vehicle, comprising: a torque requesting module that generates a first torque request for a spark ignition engine based on driver input; a torque conversion module that converts the first torque request into a second torque request; a setpoint control module that generates air and exhaust setpoints for the spark ignition engine based on the second torque request; a vacuum requesting module that requests an amount of vacuum within an intake manifold of the engine, wherein the setpoint module selectively adjusts at least one of the air and exhaust setpoints based on the amount of vacuum requested; a model predictive control (MPC) module that identifies sets of possible target actuator values based on the air and exhaust setpoints, that generates predicted parameters based on a model of the spark ignition engine and the sets of possible target actuator values, respectively, that selects one of the sets of possible target actuator values based on the predicted parameters, and that sets target actuator values based on the possible target actuator values of the selected one of the sets; and a throttle actuator module that controls opening of a throttle valve based on a first one of the target actuator values.