OH boy.. where to start.

Smack your hand for not fixing the knock issue originally (that's if you didn't...if you did..your good)

Kinda sounds like a maf sensor, but it could also be sounding like a plugged cat. Did you change the plugs at the same time? I'm going to jump around further and ask.. are any plug wires touching the O2 wiring? That does this kind of thing as well.