jtmvt Posted February 16, 2009 Share Posted February 16, 2009 So on Saturday, my tuner tweaked my tune due to some issues I've been having, namely some noticeable hesitation pulsing at partial constant throttle. He determined that my front O2 sensor was reading some funky high readings. The dyno sensor and my wideband AFRs matched up pretty closely, but my car's front O2 sensor AFR readings were reading way too lean for the actual conditions. For instance, when the dyno and my wideband read AFRs of around 12, the O2 sensor would read like 17. Also around peak boost, he said it jumped from 11 to something like 20 when the boost was pretty constant. I've got a new OEM front O2 sensor on order from Subaru Genuine Parts, but I guess my question is...what is it with these front O2 sensors??? I already had this replaced around 4 months ago, in which I got a CEL code indicating the problem. This time around, my car hasn't thrown a CEL code, but my tuner said that likely happens when the sensor stops working altogether and just reads 14.7 constantly. In this case, its just reading incorrect numbers and causing hesitation while driving under partial throttle. Anybody else experience something similar or know why these front O2 sensors seem to be crapping out so quickly? Link to comment Share on other sites More sharing options...
testes1010 Posted February 16, 2009 Share Posted February 16, 2009 My WRX had 103k miles on it w/ the original factory sensor, I really haven't heard of 'that' many failed o2 sensor, at least not low mileage failures. A pre-o2 sensor exhaust leak will cause some flaky readings. Link to comment Share on other sites More sharing options...
jtmvt Posted February 17, 2009 Author Share Posted February 17, 2009 Recently, I had a header leak, but that has been fixed. Link to comment Share on other sites More sharing options...
lheinlein Posted December 28, 2009 Share Posted December 28, 2009 Did the pulsing issue ever get resolved? Link to comment Share on other sites More sharing options...
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