is there any service you can do on a o2 senor? can you show a diagram it's placement?

 

any service or cleaning to improve a o2 sensor on a 1984 928? can you show diagram as to it's placement? approx cost if needed replace?

 

There is no service you can do to an O2 sensor. It is under the passenger side floorboard, between where the 2 exhaust pipes come together. Takes about an hour to replace or so. The wire runs through a grommet on the passenger side of the central tunnel, and into the DME/fuse area.