Originally Posted by CirrusWRX
Was ANYTHING else done on the dyno AT ALL? When it comes back, is it at idle right after you turn the car on? Do you drive for a bit and THEN does it come on? Give a little more detail. Likewise, who tuned your car? Is there a chance your car is running way too lean and the code is truly telling you something that's "accurate"?
It's also possible the uninstall/reinstall damaged the o2 sensor. LOTS of possibilities, but you are on the right track focusing FIRST on "OK - what changed most recently?" And go from there. Did they mess with your airbox when on the dyno? Possibly bumped something or a clip? etc...
I was tuned at the dyno, that is it, no parts added/removed. AFR @ idle is 14.5 to 15.0 according to my UTEC. If I let the car sit for 3 minutes idling it will come on, if I drive it I can get a few miles on before it comes on. I will give my full list of mods:
Walbro Fuel Pump
3" Catback to Apexi N1
Blitz SBC-ID Boost Controller
I am going to pop out the O2 sensor today and check it out. Also, I'm going to try cleaning the MAF