I've recently had codes pop up for O2 sensors upstream (precat) for both left and right sides. When ordering parts, I recieved downstream parts (saying they work for both sides, but when looking under my car, they clearly do not work both sides...as one connection is green (left) and one is blue (right). When looking for upstream (assuming they are connected by/near manifold) they are black six pronged parts... (the driver side "left" is for sure, did not check the other). Does anyone have a diagram for 04 g35 coupe 6mt?? Or could tell me part #'s to look into buying for the upstream precats?? Part sites like partgeek.com or rockauto.com are confusing me. Thank you.