Ok Just an update, I got a Bosch Universal 4 wire O2 sensor for cheap and it works great, but one thing sucks, I replaced it and found out that when I had the bad O2 sensor in there, I think it made my car run bad but I couldnt tell, I know there is a difference because I get about 80 more miles to a tank of gas....:-).

If the O2 sensor was not working the way it should can that cause my CAT to build up crap and clog? Because I just moved to Bellingham and out here there are no emmissions tests, so I could just take it off, but in a way I dont want to....

Should I save and get a high flow cat, or just take it off and run a straight pipe?

 

Yes, a bad O2 will definitely help to clog your cat because you will be running much more rich than normal. You can do either about the CAT if there is no emissions. Your call.

 

If I take off the CAT, will I spit out any black smoke? I know a few people who took off there cat and at WOT black smoke comes out the exhaust? I know this isnt normal for a 1.6, but removing the cat from a 1.6 isnt normal....so.... I just dont want to have nasty black smoke or exhaust that can make your eyes burn if you know what I meen..

When I see somone spew smoke when they launch, it makes me think there car isnt tuned right, and it makes me think that there car must not run well, and I dont want anyone to get that impresion of my car or me...