My daughter's 1992 2.3 L 4 cylinder mustang has a noise which seems to be coming from under the valve cover. When it's idliing it sounds like a rat-tat-tat rattle. When you rev the motor, you don't hear the noise while the motor is speeding up, but when the motor is slowing down it makes a loud growling or clattering sound. While you're driving, if you let up while in drive, it hardly makes the noise. If you put it in L1 or L2, run it up to about 3K rpm and then let up it makes the clattering sound. What's making this noise? I replaced the timing belt because it looked worn and replaced the idler tensioner for the timing belt. I put it back together and it was still making the noise. So, I removed the valve cover expecting to find a collapsed lifter or worn cam or cam follower. Everything looks good. All the cam lobes are smooth. There are no wear marks on the cam lobes or followers. I rotated the camshaft several times, checking the tightness of the followers (by hand) each time the cam lobe was at the lowest point on a follower. I don't see anything wrong. Can anyone give me some advice on finding this noise. Does anyone know any troubleshooting techniques for the camshaft / cam follower assembly? It appears the head on the 2.3 L Ford requires a special valve compressor tool. I couldn't do it with the universal overhead valve tool. Does anyone local to Houston / Katy have the below tool which is specially made for the 2.3 L ford? http://207.97.196.162/index.asp?Page...OD&ProdID=2067 I'd like to borrow (or rent) it if you do. Thanks, Boz