Bad MPG and loud

My Geo is really loud. Kind of like a fart exhaust but coming from the front. It also gets bad gas mileage. Certainly not the 30 MPG I should be near.

I'm thinking catalytic converter.

You likely have an exhaust leak, likely between the exhaust manifold and cat, but you might also have a cracked exhaust manifold.

I gutted the cat and it runs a lot better. Now I will check for an exhaust leak.