hello i have a 2000 monte 3.4L and my svs light is on.. code was P0300 or random misfire.. replaced plugs wire coils egr and when im on a hill it doesnt upshift unless i let off the gas.. car runs really sluggish burns too much gas rough idle sometimes.. the check engine light is not on.. im lost on what this problem is can anyone help???

 

Sounds like a bad catalytic converter

 

so if i unbolt the cat from the manifold would i see any difference?? i know it would be loud but i wonder how can i even tell if its bad..?