Quote Originally Posted by buck531 View Post
Please don't go WOT if you don't have the front o2 sensor installed. You are making the car run pig rich (it fails into rich mode so you don't blow up the car). Ive been fine with bosch o2 sensors. I'd get a sensor from sparkplugs.com. A denso. I've had too luck with them in the o2 sensor side of things.
the front o2 sensor is the stock one, when the new cat was installed the downstream o2 sensor died (threads came off) so bought a new downstream o2 sensor. Just not sure if getting a new upsteam O2 sensor is worth it if the current one is working.

Also, so far with the new cat system and downstream O2 sensor I haven't had any engine codes come up yet. Drove about 150miles so far so maybe I'll get lucky.