normally if it's the CV Joint, it's a Clicking noise noticed when accelerating, not when your letting off the gas. The reason that it clicks is because it's put underpressure & can't handle it anymore. Turning on it while accellerating puts even more pressure on the joint, there for it clicks more. When you let off the gas, there is less stress, so it won't click. Unless he is describing the problem wrong, i doubt this is it!