My cat's were plugged bad enough that the CEL was flashing at me. In my case, the idle was fine. My top speed dropped to 65 mph, though. That's pretty scary on the interstates around here. <img src="/forums/images/graemlins/scared.gif" alt="" />

I'm with the others. Fix/check your wiring, then see what other problems you may have. I doubt your cat's are bad.