I have a quick question. Hopefully someone can help me out. I have recently installed a new clutch and am in the process of breaking it in. However, out of the blue, my car has started idleing really rough and sounds a lot different. It backfires very often and I cant quite figure out why. I am thinking it might be the O2 sensor? When we took the tranny off is it possible it could have gotten dirty? I am going to get the car scoped tommarow to check the check engine code. Any ideas would be very much so appreciated. I am running a catless 3" exhaust and had a previous check engine code of small leak in the emissions system. I am hoping that there is a new code being thrown so that I can get an idea of what else could possibly be wrong.