Is it engine noise or drive train?

Engine related: Check your oil. If it's low, you could be hearing lifter noise that goes away after oil gets splashed around.

Drive train related: shoot some grease into all zerks as mentioned. Also check your CV boots. If they're split or torn, you'll need to replace ASAP.

Of course it could be something as simple as a rock caught between your rotor & the dust cover on one of the brakes or one of your heat shields rusted loose & banging on your exhaust.