Why does your power steering rattle but stops when you turn the wheel?

This is due in part to both the intake manifold and the power steering itself. The reason it stops is because the air intake is being diverted away from the Power Steering belt and is in a sense, "balancing out the intake" -- in order to remedy this problem, you need to replace the power steering itself and put new power steering fluid in it, only then will the rattling stop.