As PatriotsMike111 said, You have to be in the lead. The easiest way is to nitro into the lead. As soon as your position changes to 1st, fire the shock power up and simply slow down/stop. You don't have to stay in the lead and you can use carver to absorb the shock spheres.
This part popped for me before I'd even reached the 1st sphere! I was a bit slow!!!
As for the other 3 parts, it's just keep trying. Eventually you'll get lucky. I'm still grinding the 250 shocked cars...