Hi i learn the basics of car race. i refer the J-car tutorial.and give the scripts to my car. But the car was not run successfully. The car wheel does not stand in the plane initially. its wheel move to infinite position. I don't know the reason for that. and also the car does not rotate. Thanks..
Car physics is a pretty advanced topic. You need to worry about the center of mass, wheel colliders, etc. I would suggest you start by making more basic types of movement and not worry about making it feel like a real car, yet.
If you really want to get cars working, you should read up on the various types of Colliders (including Wheel Collider, but they are especially hard to use), and rigidbodies. Make sure you read all the documentation.