Couple days ago my car began running realy rough and service engine light began flashing. It was alredy on due to needing a o2 sensor (after cat converter) so i took it to part store and computer read misfire cylinder 2. I took coil pack from #2 and moved it to #1 to see if problem followed and sure enough it did. I replaced all 4 of the coils as well as the o2 sensor. Now when driving the car has no power when acelerating and when it kicks down to pass other car it makes a shhhhhhhhh sound and has noooo power. As you drive the peoblem gets worse and worse. Someone said that it sounds like the Catalytic converter is stopped up. I dont know what to do.

Yup! It sounds to me like you have been told correctly! This is the very reason that I preach to people that it is NEVER OK to continue operating a vehicle with the Check Engine light on. The Check Engine light has one mission in life. Its purpose is to let you know that there is a problem in your engine control system that can damage your catalytic converters. Ignoring this light and continuing to operate the vehicle anyway causes the problem that you are now experiencing.

What to do??? Get up off of the BIG BUCKS and replace the high-dollar catalytic converter that has been destroyed. Then diagnose and repair ALL fdault codes in your engine control system so you don't destroy another one.