I have changed the rear o2 sensor because of rough Idel rich fuel smell and some black smoke. I still have the problem now code calls for bank 2 sensor change. Any other things I should look for. Possibly MAF. Thanks

I have two 1998 V70s - a T5 and a non-turbo. My OBD scanner (laptop, software and adapter) showed the T5 rear sensor working properly but the same scanner never showed anything for the non-turbo sensor voltage. I was sure it was my wiring, O2 sensor or ECU. I swapped them all and worked on the problem for a month. I finally capitulated and took it to an Volvo independent. With his expensive scanner, he just replaced both O2 sensors with Bosch ones from FCP. My mistake was thinking that if my scanner worked for the T5 it should work with the non-turbo. Whatta mistake.

Interesting, because the rear O2 sensor has a longer life than the front O2 sensor. Left bank = front, rear bank = rear. Check your wiring and/or check for a dirty connection.

Most rich running engines are because of a vacuum leak, check all of the elbows on the vacuum lines at the intake manifold. Also check the lines to make sure they are not plugged up with crud.

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)