I believe that's not a problem, the construction of the pedal set is very rudimentar, the "arms" that hold the pedals and connect them to the potentiometers are actually hollow and entirely made of plastic, inside the hollow plastic goes a very thin piece of metal which is responsible for activating the potentiometers. The rattling noise is the result of the very thin piece of metal moving inside the hollow structure and being hit by plastic. That's the annoying noise you're getting, hard plastic and metal.
But again, it's a very cheap wheel so even if the motor is quite fancy and provide great FFB, the rest of the package is poorly made to save costs. Mine sounds like that too, it's absolutely normal.
