about my 2004 timing chain noise

Below is the question i ask a few days ago i got a few responses about
heating shield my car was put up on a rack and the exhaust and catilist
converter was checked and the heating shield also nothing wrong there i
started the car up and listened it sounds like it is coming from inside the
timing chain cover area i shut it off and pulled back the cover and pushed
on the timing belt it seems tight still driving it it only really makes the noise
when started cold after it warms up it doesnt go away but it dies down and
when i drive it like i said below after i get it up to crusing speed it stops
even when i am sitting still i can rev up the motor and if i rev it up high
enough it will stop also A few days ago i was making a trip about 60 miles
one way i got turned
around and at slow speed my aveo started making a load rattling  type
noise but this only happens at low speed when i get it up to 40 mph or
higher sounds stops it is coming from the timing belt area under the cover i
have been driving it no warning lights no loss of power or anything oil level
is good i have so many people telling me different things what could it be
like i said it runs fine when up to speed and after it warms up the noise
dims down no smoke or warning lights runs good when driving no loss of
power or anything..