In the original MK if you turn too hard for too long you start skidding (and eventually spin out), but it's not a powerslide in the sense that you can turn tighter/faster than you otherwise would, or that you get a speed boost if you time your exit from it properly.
If you launch from a jump (e.g. yellow panel or feather) and hold the hop button down as you land into a turn, it's a powerslide and you can exit it in the same way as any other powerslide.
In the original MK if you turn too hard for too long you start skidding (and eventually spin out), but it's not a powerslide in the sense that you can turn tighter/faster than you otherwise would, or that you get a speed boost if you time your exit from it properly.
If you launch from a jump (e.g. yellow panel or feather) and hold the hop button down as you land into a turn, it's a powerslide and you can exit it in the same way as any other powerslide.