I posted this in the Belta owners/fan club thread. The 1KR-FE is optional in both vehicles so this information would be useful here as well.
First of all you will have to open up the red circled clamps in order to proceed any further.
That is the throttle body below the golden ring, @Zubair530.
Take all four clamps off of the air intake assembly. There are two other areas which you will have to move the assembly from.
First of all you would have to take the air filter out, just lift the assembly a little and pull the filter out it's flexible so don't worry about breaking it. Just do yourself a favor and don't rush. Out goes the air filter.
Now you will have to pull the assembly upwards very carefully. The circled fixtures are what you will have to take care of. This is what is looks like when the assembly is taken off.
Now once the assembly is off, place it in a safe area where no one steps on it.
Just behind the ignition coils is the throttle body, here is a view of it.
Here's the throttle bodies view from the inside. You can clean it with a carburetor cleaner spray it won't harm the throttle body.
Notice this fixture clamp, it's covered with carbon deposit. Clean it up with a tissue or a old rag before putting the assembly back on. You're going to have to use your pinky finger in order to clean it up, the area is quite congested.