Very Interesting question and I say good one too. Your thought process regarding the Throttle body would be right if you had Carburated engine in your car but fortunately it is equipped with EFI engine. Sorry but carburetors were phased out because stricter emissions regulations required a more precise way of delivering fuel far beyond the fundamental mechanical ability of the carburators.
Fuel injection controlled by a computer has become the norm and permanent replacement for effective mixing of fuel with air. Among the components of this system, is a vast array of sensors, wires, coils, valves and hoses that are required for collecting data and delivering commands.
So you are stuck with a EFI Suzuki Liana and the TB (throttle Body) in Liana or any other efi car comes with Throttle position sensor. The Throttle Position Sensor is another important part of the data collection puzzle. It is found on the side of the throttle body assembly where air enters the intake manifold on its way to the cylinders.
On carburetors, the throttle body features a flap that opens and closes to control the amount of air entering the engine. Likewise, a similar flap on a fuel-injected engine also controls the amount of air in order to increase and decrease engine speed.
The throttle flap or plate is linked to the accelerator pedal, which we all know is used to control the amount of power put out by the engine. In order to increase the acceleration of your car, you apply more pressure on the accelerator pedal. This makes the throttle plate open wider. The wider it opens, the faster the engine operates and more power is created and delivered to the wheels.
All this movement is vital information to the command center that must dictate the amount of fuel that will be required.
The job of the throttle position sensor is to offer feedback on the exact position of the throttle plate to the engine controller so that it may begin the process of calculating the fuel and timing requirements for efficient power delivery.
The sensor acts in a way similar to volume control on a radio, increasing and decreasing the voltage that passes through it as it turns. The voltage ranges between .5 and 4.5 volts and travels to the engine controller via a common wiring harness that carries other signals as well. The throttle position sensor reacts to all the throttle plate movements and therefore creates a voltage signal relative to its position. The voltage created is then interpreted by the engine controller as to the amount of power demanded and so delivers the amount of fuel that will be required.
So what I am trying to say is that the extra gap in the cable of your TB is useless to you coz Flap in the TB can open to a certain point and beyond that point it would actually be restricting air rather then allowing more air. That is because it has already reached its Horizontal level. And Yes it is normal to have slack in the cable pulley system TB of your car.
