I'm out driving today and all of a sudden a feel a loss of power while on the freeway... I get off the freeway and I hear this metallic screeching sound emanating from the engine. When I got home I opened hood and it's a very loud high pitched metallic screeching sound whose frequency seems to correspond to one cylinder firing. But with so much other noise under the hood, I can't really pin point where on the engine it's coming from I have good oil pressure. When I rev the engine, the sound seems to go away until it gets back down to around idle speed. I don't have a noticeable misfire or anything like that. I took off the valve covers and the rockers seem to be ok. No broken valve springs. Pushrods seem fine. Nothing seems to be rubbing on anything else. Ugh...anyone have any thoughts?