I jus recieved my pacesetter longtubes for my 07 Sierra Vmax 4x4. Im gonna do away with the cats so what am i to do about the 2 sensors that are after the cats now. The guy at the muffler shop said he can weld some threaded adapters to screw them in but i doubt that will work. Im gonna go with a bear tune after the install to eliminate any codes that may be thrown.

 

Leave them plugged in and either install them into the exhaust or zip tie them to the frame.

You'll want to do this to stop the computer from doing cat tests at random. It will do them if the rear o2 sensor are unplugged and it doesnt matter if you tune the codes out or not, it will still do the tests no matter what. It's not a huge problem per say but annoying if you have a wideband and see it happen all the time.