Engine noise

Well i been on af for alittle while now.I need alittle help now cant put my finger on what it is.But i can hear my engine on the inside of my car but it goes away around 2/3gear and is fine from then.I was thinking that the cat might be going bad.

Scoot

And what car/engine is this?

And what car/engine is this?

Its a 1996 Cutlass Supreme 3.1

Scoot

Well i been on af for alittle while now.I need alittle help now cant put my finger on what it is.But i can hear my engine on the inside of my car but it goes away around 2/3gear and is fine from then.I was thinking that the cat might be going bad.

Scoot
What kind of noise is it exactly? a ticking? a rattling? a knocking? a whining? etc.