94 integra... got my cat taking out due to clogged up very badly and needed a new muffler as well, now have a pretty good muffler and pipe where the cat was. a bung was put there for the o2 so all that is good i assume. I am getting a code 41 sometimes after the car heats up. code is a o2 heater sensor according to the blinks. I am trying to troubleshoot but cant figure this out. Thanks.