Okay so I recently picked up an 03 mazdaspeed protégé. The upstream oxygen sensor connector was completely melted at the harness from being up against the exhaust manifold. I got a new o2 sensor and spliced(harness side) a Mazda protégé connector that I got from a junkyard. Although even after this I still have a CEL for no circuit activity for upstream o2. Not sure if the PCM could be shot as there isn't a 02 fuse and it could've shorted when it melted. The other thing I noticed is that coming out of pin 60 on the PCM, the wire turns into what looks like a coaxial wire after a few inches. The wire that goes to the PCM is pink with a blue stripe, yet a black wire feeds into it and goes out to the o2 sensor. This wire has white insulation after this converging. Anyways I found that the outer wire abruptly stops before the 02 connector while the wire underneath goes to the plug. I spliced these together to no avail. All in all my engine runs in an open loop constantly and has a rough idle and acceleration. Not sure if I should be looking at finding a wiring harness or new pcm, but any help would be great.