I'm back again, engine noise. (video)

[ereigaM]

I pat myself on the back because first go, no leaks or issues and the new gasket for the transmission is OEM and not the flimsy kind that I apparently had before. Glad I took precaution and bought it.
I finally changed the oils and their respective filters. However, still having misfires at idle and when trying to give a lot of gas. Haven't checked the spark plug/wires by disconnecting them yet. Sounds like there's something loose on the back end of exhaust system, has a veritable rattle. Next paycheck I'm just going to get it looked at but I tried.
Small side note, I think it's possible one of the pumps is going out. Something on the belt line is making a lot of noise as it spins. It's not the idler pulley, however, because I went and changed that too, as I wasn't wrong about it, it was starting to go.
Thanks everyone. I really appreciate the help you've given me and that you're here. I love my car and I can't wait until all I have to talk about is modding it.

[ereigaM]

Hey, I thought I'd come back to report this. So apparently what was bogging the system down was bad spark plug wires. After I changed them the engine sounds much much smoother. Before I had done that I took it in for emissions and it failed wildly. If I recall, the HC emissions was 8x the limit and the CO was way over as well. I did a tad bit of research into what might cause both of those to go and the catalytic converter was pretty much the first thing mentioned. Now, I'm not sure how they go about testing it but the emissions test had the CC marked as pass. Either way, I'd like to change it out for the experience and so I don't have to later. However, I don't know a thing about welding or if that's even entirely necessary for just the CC. I have a factory manual for the car which has been a great help.

For now, I'm asking your opinions on what's best for installing one. I don't know if it is better to start a new thread or not.