What would cause my car to run very loud with no apparent warning? on 2003 Pontiac Vibe

The car began running very loud especially when started and whenever I hit the accelerator. The car is easily 2x louder than normal. It seems to drive okay, but I haven't taken it very far since the noise started. No check engine lights turned on.

2 answers
Could be a problem with the exhaust or muffler. If you cant look at it yourself, give us a call and we will be happy to help you know whether it is something dangerous or not.
Cracked exhaust manifold?