i know i know this seems to be all too common, but i cant get rid of em. Ever since i put the headers on and had it tuned its been throwing these 2 codes (P0133 and P0139). Ive tried everything i can think of including checking resistance in the extensions i bought for the O2's (which btw are 0 in all wires in both ext.'s) So my understanding is as long as its reading the O2's as "slow" the PCM will not use the signals from the O2's....am i correct? I've replaced both O2 sensors....twice...with the same result each time...and yes i only use the AC Delco sensors, I was told to use them specifically because of problems with Bosch and the like) I was also told that it has to be "programmed" out of the PCM. Well my questions to that is will the PCM use the O2 sensors to trim the fuel curve if its "programmed out"?? My concern with all this is the normal driveability of the car is compromised in all part throttle instances...am i correct? I would think the car is running in open loop mode constantly...yes? Im just worried that running in open loop for extended periods will eventually foul the plugs...make it run rough..etc, etc. Is there anyway to get rid of this and really fix the issue, or am i just stuck with 133 and 139 and open loop modes forever? Damn i just realized i wrote a book....my apologies. Thank you in advance for any help with this issue

 

If you tuned the pre-cat O2 sensors out, you would be running open loop. In open loop, there is no PCM response to the signals from the O2 sensors. If something changed in the system, MAF calibration, fuel pressure, vacuum leak, etc., the PCM could not respond by correcting the long term fuel corrections.

Have you verified that the O2 sensor heater wires are getting 12V, and that the heaters are working?

 

i havent directly checked the supply voltage to the heater circuit, wouldnt it throw a code for heater circuit malfunction if they didnt work? Im for sure going to check anyway...so u think they're just not getting hot enough? For sure though im going to start there, anything u suggest i will try

 

well i was never able to check the voltage, family was sick, i was sick...didnt happen. Anyway they work now...so not sure whats goin on there, only thing that changed was the addition of a 52mm tb, touched nothing else.
this is the first time they have worked since i did the headers and tune in feb. Weird