How can I reduce inertia of a pawn which is using Add Force?

I fixed Linear Damping value, and Inertia Tension values but it does not worked at all. If I once turn the pawn to the left, it just keeps going left crossly, even if I release the steering key. I like this effect but I wish I can handle the rate of sliding. I am not using Vehicle class.

Example Vid

Depending on the exact outcome you want, there are multiple ways to approach this.

(Quick Fix)
Based on the video provided I would firstly recommend you play around with adding a physic’s material on the ground experimenting with different levels of friction for desired results. You could also try increasing angular damping.

However I warn you about these quick fixes, although they may work, they probably will not be suitable if your looking for complex or advanced gameplay manoeuvrability.

For more complex movement I would try implementing a blueprint system that detects angular movement and reduces speed accordingly. Something like:

Comparing speed and (global) direction of movement with current rotation in a branch that measures and limits the rotation of the angle against the speed and direction of the movement. Then all you need to do is create a final Boolean that leads to a function which reduces its speed on a giving angle.

I know this probably sounds a bit confusing so if you need me to elaborate I can.

Yeah angular damping worked thx