Ok long story short i had to have a new flange welded on my stock downpipe. I recently put on a cat back exhaust and i am throwing a code for both oxygen sensors and the maf. The exhaust pipe is tweaked due to what im assuming is the flange on the downpipe was not welded long enough out. I went to clean the oxygen sensors and discovered that the bank 2 o2 sensor is being pressed against the heat shield. The wires are what is being pressed against the heat shield. So i figured ok no problem I have a new downpipe on the way so no big deal i can wait. The car will every now and again after idle for about 5 min will start loping really bad, almost about to die. I talked to someone about it and they mentioned that only the first o2 sensor will cause that. So my question is will one bad o2 sensor reading cause the other one to read bad as well.