Low engine power output/little movement on the turbo pressure gauge and rattling from the turbocharger: Conditions

On certain cars, the clip holding the turbocharger pushrod to the arm on the wastegate valve can come loose. If the clip does come loose, the pushrod can slide off the pin on the wastegate valve arm. As a result, boost pressure control will not function and the valve disc will cause a rattling noise from the turbocharger.