Here goes an interesting problem. First started off with the check engine light coming on this past spring. Researched the code for my '95 volvo 850 glt sedan and it was a 436. I talked with the guys at IPDUSA and bought a new rear O2 sensor and installed it, cleared the codes and ran fine for about a day and half before the check engine light came back on again. Checked the codes and it was once again the 436. This time cleared the codes and disconnected the battery cables for the day. Came back to it and this seem to work for about two days then the check engine light came back on. Contacted IPDUSA guys again and this time they suggested that I check the temp before and after the Cat. Got back to them with the results and the Cat seems to be working the way it should. Does anyone have any ideas on how to fix this pain in the butt error code from coming back again? I just cleared the codes again this evening and nothing has changed. I can be emailed at rpiescik@comcast.net. I look forward to the replies. Thanks.
Bob