from my handy chiltons manual, bank 1 should be against the firewall as the front of the engine faces the passenger side. there are 2 O2 sensors per side. 1 on outlet of each exhaust manifold and then 1 downstream of each catalytic convertor. P0138 says O2 sensor circuit high voltage bank 1 sensor 2. get it up on ramps and follow pipes to find. hopefully it will be a simple swap and not a pita to get to. good luck

 

attached is the pic of the sensor. When ordering what would this be called? I usually order from www.rockauto.com

again. any help would be great! Is it the downstream right or the downsteam left?

Thanks

Adam

 

As noted, yep, its the Firewall side, downstream or second O2 sensor After the Cat converter.