[funboy6942]

Call me silly but if that cat is not working right your car will run like crap because the computer is trying to make up for what its sensing in the exhaust. ALSO if your throttle positioning sensor is shot, it will run bad for the computer has NO idea where the trottle is at and is just guesing as to how much fuel to air it needs.

I would also start the van, have someone rev the motor and see just how much exhaust is coming out the tail pipe, for if its being gunned, and hardly anything is coming out, that cat is still clogged, but in any case, with a computer controlled motor, you need the cat to be working as it should or its going to reak havok on you.