I have a 2000 Honda Passport (2WD Automatic) that has a got an exhaust leak right at the exhaust manifold / header (from what I can hear). I also hear a really annoying sheet metal rattling sound when the engine idles and gets even louder when I step on the gas. I think it’s the manifold gasket…

Has anyone has this problem or know what causing it? Any easy fix?

...an exhaust leak right at the exhaust manifold / header (from what I can hear)...

At the cylinder head or at the outlet of the exhaust manifold? The S.S. braided flex joints have been know to break, or check the EGR feed pipe.
The rattling noise sounds like a loose heat sheild somewhere.
G/luck
Joel

At the moment I don't know if its at the cylinder head or at the exhaust outlet... Will look into it asap... But the heat sheilding could very possibly be the cause of the rattling.