Check to heat-shield at the catalytic converter because something is loose
Depends on where the noise is whats making the noise. Can you be more descriptive of where and what?
it may be your tire alignment. your tires may need to be re-aligned. a couple of months ago my car started making a rattling noise when we would go about 70 mph on the highway. we found out are tires needed to be aligned again.
bad transfer case
your Imagination.... :)
Inspect the catalytic converter heat shield.
start by checking a/c compressor.
Check wheel bearings - quickly! Very dangerous left unrepaired!
No way of telling you without hearing it and seeing it. Have a trusted mechanic inspect the car for you before you get stuck on the road.
usually a loose bolt
There are a number of causes for a rattling noise that occurs in a car. These include low oil and an engine that is faulty or going out.
I had this same problem so I opened the hood and come to find out there was migit materbating under it
The batter is low