I've been getting this code, P0140 - Downstream HO2 Sensor Stays at Center, on and off for the past couple months. Tuesday 3-1-2011: I was about to go get my car inspected and the check engine light came on... So I had to cancel the appointment. I checked the code and it was P0140 (listed twice?). I drove around and back home, then went out later that day for a drive around the roads and then filled my gas tank. About a mile after filling up I was sitting at a red light and I noticed the CEL went out, so I continued onto the highway about about a mile down the highway the light came back on. The light stayed on from here. Wednesday 3-2-2011: CEL was still on (same code). Thursday 3-3-2011: CEL went out in the morning when I started my car and stayed off for the rest of the day. Friday 3-4-2011: CEL is still off, and has been off, for the whole day. I finally deleted the code, P0140, when I got home from work. Hasn't come back on yet.. Saturday 3-5-2011: Unknown yet... :hyper: I have heard that the P0140 (Downstream HO2 Sensor Stays at Center) doesn't necessarily mean that your Rear O2 Sensor is bad, but it seems to be more common that there could be a wiring/ground/short issue with the wiring between the Rear O2 Sensor and the PCM. Don't like posting links to other forums, but this one has what I am referring to above. ^ P0140 O2 Sensor?? Also, as you know, I deleted the code last night, and I am going to get my car inspected today. Since I deleted the code, will they see that and fail me or?? I know my friends Honda passed, he deleted the code right before he pulled into the bay. I also have a Chevy Lumina that was throwing a code and I deleted the code before I went to inspection and it passed. So I know it depends on the manufacture, thats why I am not sure about Mitsubishi.