Abstract: An accelerator control linkage for the engine of a vehicle which maintains a maximum vacuum in the intake manifold of the engine. The linkage of the accelerator normally allows the throttle to open only when a predetermined vacuum is present in the manifold. This is accomplished by a bellows connected to the intake manifold so that the force of the bellows on the rod is proportional to the degree of vacuum in the manifold, with a tension spring, mounted to the rod to oppose the force of the bellows, in use, to accelerate by opening the throttle when intake vacuum is diminished, requires more force on the part of the foot of the driver, with less pedal force required under conditions of high vacuum to encourage driving the engine under most economical conditions.