Hi guy's:

I have a 1999 v70 glt 125,000 miles.

Check engine light came on combined with poor idle and erratic performance, scan apparently indicated o2 sensors are faulty. (I did not question the diagnoses)

both O2 sensors replaced with Bosch units

1 month later w/ not very much driving CEL comes on again with the same bad idle (hunts from almost stall to 1000 rpm) and poor performance

scan reveals codes PO 138,PO 134, PO 140.

resetting the error codes allows the engine to operate normally but CEL is still lit up.

Are there any troubleshooting tips you can suggest

thanks

john

 

I would take it back the new sensor might be bad.