So after this backfiring happened i noticed weird stuff coming out my exhaust.
thread to backfiring.
anyways i dropped the exhaust yesterday and took it to my buddies house where we wanted cut the cats open and check on the or remove them because they sounded like they were screwed.
long story short we cut the secondaries open and there was nothing in there!! lol
so we thought it might be piled up in the muffler so we cut the muffler open and i guess we cut too short. but on the uncut side i think contains padding and straight pipe with holes in it, but the cats probably passed right through it. so I'm going to weld it up tomorrow morning and re install it on the car
in the mean time here is a pic of the the progress