With a faulty vacuum pump on your intake system, the level of draw or vacuum available for the many systems on your engine requiring it will be insufficient. This vacuum generating component is also referred to by some manufacturers as a suction pump. It only purpose to produce additional vacuum for the many systems on the vehicle so they can operate with this lightweight but reliable system for the opening and closing of valves and solenoids. These systems include both those on the engine and the accessories like the vents in the passenger temperature control system. Without this component functioning properly, the engine might not start or will run rough if it is capable of starting.
The vacuum pump is a mechanical pump that generates a vacuum when it is operation. In theory it operates in reverse of other pumps since it draws in air instead of pushing it out. This is accomplished by a piston moving inside the housing unit that moves. The vacuum is created on the intake stroke instead of harnessing the power of the combustion stroke like in an engine. The vacuum created by the suction pump can immediately be used by one of the vacuum system on the vehicle or it can be temporarily stored in the vacuum pod till it is required.
The replacement of the vacuum pump requires the location of it be known. There is either electrical suction pump or a mechanical one that can be on a vehicle. The mechanical pumps are located somewhere on the engine and receive their power from the rotation of the engine. This location is generally around the cam so it can tap into the rotational power there. The electrical type is usually on the fire wall near the center of the vehicle. This allows for the vacuum lines running to the engine be as short as possible.