I recentlly noticed a random clicking sound (random and sparatic, not like valves) that is only present when im coasting with my foot off the gas. As so as I touch the gas, even the slightest bit, the noise stops. Engine was warm when the problem was noticed. Temp reads normal, normal revs at all points.
Also, perhaps related, when I put the AC on it will run fine for a bit then make a horrible sound like a dying girrafe (if you saw the south park movie its almost exactly that sound).