Front O2 sensor is acting up

[mko]

Ok, when it wasn't so cold out 30-40 deg, I was getting code 11 /upstream O2 sensor/, but i never had any problems and i was getting good milege. I'd clear the code, but it would come back after a day or two. Now, when it's 8 deg outside the CEL hasn't been on for 2 weeks. What's going on? Can anyone explain it? Sensors are 3 months old.

 

[ktmrider]

Ummm, you got a 91-92 GVR4? If not this site will be thin on info.
Sounds like a 2g+ DSM/MMC vehicle to me, we only have one O2 sensor near the turbo.

 

Code 11 is the correct code for OBDI cars. Depending on what he is using to read the code it may say "upstream" even if there is no downstream sensor. 2G cars are OBDII and would have a code like P0200 (not the exact code, but thats how they are numbered.) As for why the code would disappear in cold weather, I'm not sure.

 

[ktmrider]

Doh, I focused on the wording and missed the Code 11.
Log the O2 output and report what you see for both hot and cold.