I've been having some engine codes for the past while 2 of them were for the O2 sensors up and down stream , I changed the up stream but not the down so far no engine light but when i scane the ecm i get a p1137 HO2 sensor low voltage during power enrichment. My air fuel gauge always goes between lean and stoch it never goes to rich not while im crusing or at wide open throttle. Is this because I haven't changed the down stream or is it something else

P1137 =Downstream Heated O2 sensor (which means second sensor, after the cat) circuit low low voltage. If I remember correctly low voltage means high readings. Your registery does not say if you have exhaust work, or on stock exhaust. Could be a bad cat, or a bad rear O2 sensor.



FU Tuning

Yeah I haven't touched the car much since I got my iroc, so I haven't updated it in a while. the exhaust has been changed its a 4 into 1 header with a high flow cat and 2 1/4 inch piping, it was all done Feb /06 and the car wasn't driven between May /06 to Oct /06 so the exhaust is still pretty new, the sensors were never changed then.
The air fuel mixture some days goes from lean to rich like it always did but most of the time it wont go to rich.