neon cape
After a cursory glance at the guide it looks to be functioning correctly, you're using is_action_pressed, so it will continue "turning" every tick that they key is pressed down. If you use something like is_action_just_pressed or is_action_just_released it would only happen once but the guide explains that "the car should move and turn. It’s still very unnatural though - the car starts and stops instantly. To fix that, we’ll add acceleration into the calculation." it's the very next step.
compact compass