[crazybrew609]

yup it's a cat... and heres why... with that car not firing it had a lot of built of crap in the cylinders.. once those new plug were put in and they take the car out of the shop and rev it for about 2 or 3 mins to make sure all the crap is out of the cylinders then that crap goes right to the cat and clogs it.. sometimes you can get away from doing that but once you do it enough ti will clog