Oxygen sensor problem
I have a 1995 Jeep Grand Cherokee, auto, 6cyl. The check engine light stays lit most of the time for the last month and when my husband used the code scanner, it indicated that there was a problem with oxygen sensor. So he replaced it and the same thing happened again with the check engine light coming on. Again he used the code scanner and it indicated a problem with oxygen sensor. Since the part was under warranty, he took it back and got a replacement. Put the replacement in, and guess what?==the check engine light still comes on, and still indicates there is a problem with O2 sensor? What gives? Is there more than one O2 sensor in the Jeep. My husband has the Jeep manual and he seems to think there's only one. Any ideas as to what to check out next? My husband said that when he took out the old O2 sensor there appeared to be some carbon build up on it. The vehicle has about 190,000 miles on it but the engine runs strong usually. Any help appreciated!