The problem is this: When the steering wheel turns slowly in place while the engine is running, feel and hear the vibration of the steering wheel (knocking). When you lean your hand on the front wheel also feel vibration (knocking). The same can be felt on the left and the right front wheel. So it happens only when the car is idling and at low speeds, while at higher speeds the problem disappears. Please let me know what the problem is. Thank you.