I've been having the notorious 301(sometimes 302) code for sometime now. Now I've read a bunch of threads and googled it. One of the possible causes is a bad O2 sensor. This is where I need help. My 00' Sahara does NOT have the California mini cats emissions. So when I talk to my local dealers all they can do is read the parts manual n tell me that there's 4 O2 sensors in it. I only have the two in the exhaust pipe one before and one after the cat. So would the one before the cat still be considered the "upstream" sensor or not?