my cat is fawked. I had a cel for coil and/or wires. I changed my coil and wires and now the cel is still up for bad cat. I haven't changed the cat tho. I had the battery unhooked for about a week while I waited on my powdercoating to be done. The car didn't throw a cel until about an hour or so of driving. I'm tempted to gut the cat tho. The mechanic that diagnosed my car for me (had a code reader thingamabob) said where the coil went, the car was probably only running on 2-3 cylinders at times and the other cylinders were just putting unburned fuel into the cat. So, the cat was soaked in gas, and when the car was running on all 4 again, it burns the fuel and burns up the after-cat o2 sensor. Something like that. Oh well, I figure a high flow or gutted cat will give the same effect.