importkilla

Service engine light came on a while back. Hooked up the code reader and I have a problem in the left bank of the catalytic system. Think I'm going to go ahead and gut em'. Guys got any pointers? I'm just going to run with the light on until I can get some simulators. Have many of you done this? How much of an HP gain will I see? I've hear in the 6-10 hp range. I'm thinking maybe lower like 4. Anyway, that doesn't really matter to me right now, I just want to get this sucker breathing better. It's been chugging lately. My boy has asthma.