I posted about a topic similar to this - just saying so it wont seem like I'm double posting. But recently, I noticed that when the engine is cold, like in the morning, there's alot of clattering noise, kind of high-pitch clattering, like valve noise of something with the timing chain. I havent really had the chance to probe around the engine bay throughly, but I can say that its coming somewhere from around that valve cover. I have a 98 GXE and with only roughly 39,000 miles. But this noise is only loud when the engine is cold, when its up to running temp, the clattering noise is not so noticable. Is this just a normal thing? Because I only just (about 1.5 months) noticed it.

 

It's kind of hard to try to diagnose this problem with what you described... Check for loose items... If it really is coming from under the valve cover(s) then you should have it checked out.