what is the rattling noise I hear when I start the engine?

What is your question?

-New rattle -occurs when engine started, lasts seconds -same noise when put into drive -rattle can be heard when driving over curbs, tracks -sounds metallic Sounds like a loose exhaust manifold cover to me 120k

What makes this problem better or worse?

It bothers my wife

How long has your 2009 Toyota Corolla had this problem?

2 weeks