When I accelerate with WOT at revs above 2500-3000, I hear a noise coming from the eninge or somewhere near it. It sounds like a stick or something is caught under the car and is getting broken up. The first time it happened, I though I had run over a branch or something. But I checked under it and nothing was there. It happens regulary under hard accelerating. Is this some kind of engine knock due to incorrect timing? It's a funny kind of sound so I didn't think it was a knock at first, but I don't know what else it could be. Any ideas? The noise always goes away a couple seconds after I let off the gas. Thanks for the help.