The harness (the part that comes from the PCM to the O2 sensor) touched the header and the casing and some of the electrical tape it was wrapped in was melted. The 4 wires inside were fine, so I rewrapped them and put new tubing.

I'm curently chasing down a high fuel trim on that side (bank 2). Would that be a possible cause of the high fuel trim? It is only high at idle and the rest of the time it is pretty much spot on. I don't know enough about 02 sensors to know if that would cause that to happen.

Thanks, guys!

 

Any exhaust leaks 24" downstream could cause 02 sensors to read funny. Even pinhole leaks. Other than that I don't see why the melted loom would cause it to read high unless the sensor itself is faulty. How long ago were they replaced?

 

The sensors are only about 500 miles old.

By 24" downstream, do you mean PAST the o2 sensors? The car only has the front sensors - the rears have been programmed out. There IS a leak down the exhaust probably 18" after that sensor. Can that really cause it to run lean (and therefore rich after fuel trim)?

 

From my experience a leak downstream of an 02 sensor has caused weird MAF readings, rich and lean fuel readings etc. can't speak for you but it's worth looking into, of course it could be a number of things but start with the basics! Lol