Hey guys. I just picked up a 93 Accord EX Sedan. Its quite loud. It appears they removed the cat and replaced it with straight pipe, but used clamps (HUGE LEAK)...ugh! The flex pipe has a huge leak as well. The pre cat O2 sensor is missing. They have it plugged up and I don't think its going to come out to just put an o2 sensor there. My questions is should I replace the entire down pipe all the way and just weld up where the cat is? (I know its illegal) or is that o2 sensor that important for gas mileage etc? The car has a CEL I haven't had a chance to check it out yet. I am assuming its the o2 sensor or the cat. It runs pretty well but has a hesitation at low rpms. Its just a daily driver doesn't have to be perfect just want something thats get better gas mileage that my G35X (18.5) lol Any help would be awesome. Thanks guys.

 

As stated on the other site where you posted, there is only one O2. If the plug won't come out, either buy a new pipe of search in the local bone yard.....trim level shouldn't matter.