First of all you absolutely need to isolate where the sound is coming from and when it happens. You said it does NOT happen when you use throttle only. If it happens only when you pedal, and you know it is not the pedals and every bolt on the crank is tighten, then it could be the bottom bracket or the freehub. And you certainly don't need a whole new wheel for either one of them. So first specifically isolate from where the noise is coming from. Do you require to pedal with a lot of effort for it to happen or does it happen even when you pedal without much effort?
