Hi, my Lexus RX300 has 180k miles, timing belt replaced, last month while I was driving I heard rattling under the valve cover. It starts after driving a few blocks when I let up on the accelerator while coasting. If I step on the accelerator the noise stops but as soon as I let up it starts sometimes very load. If I let it sit in the driveway the noise starts and gets very load after a while. I took it to a local mechanic and he said, "beats me" lol. I replaced the bank 2 OCV and cleaned the filter with no change. Anyone has any ideas? It would be greatly appreciated!
