Has my WBO2 crapped the bed?
 

I'm not quite sure if this is a sensor problem or a controller problem but this came to my attention over the weekend.

Normally I don't do much highway driving, my daily trip to work is about 20-30 minutes, all on surface streets. In that driving mode,my AFR readings are "normal". However, on Saturday and again on Sunday I had an occasion to make a 90% highway, 2+ hour trip. On the 1-hour "out-lap" I noticed that the AFR reading on the controller (a Ballenger Motorsports AFR500) was stuck at 14 pretty much all of the time ad only changed when I lifted. There were some times when I went at "supra-legal" speeds, and then the AFR would drop into the 11's and 12's, which seemed odd. When got off the highway, the AFR readings seemed to go back to "normal". The trip back home was similar. What I did find as an added oddity was that when I attempted WOT during cruise things would start to go to hell, almost as if I was experiencing a fuel cut - sputters and stumbles (no pops, or bangs).

On Sunday (today), I did a datalog using my tablet (thinking that maybe the laptop datalog might have been "weird" for some reason) but the behavior was pretty much the same. I even did a log using my phone, but the result was the same. I stopped in a parking lot and the idle AFR now seemed to be WAY lean so I added a bunch of fuel to stop that, ad also added fuel in the cruise cells - thinking that might help things out - but the results were the same.

So, I don't know if my latest tune is crap, of if my O2 sensor is going bad (under high, sustained RPM/load conditions).

Tomorrow I'm going to go back to a known good tune and see what happens. But I've attached several files.
- 2019-09-28_8.21L; That's the outbound trip (truncated, from laptop) - at 1188 seconds is a WOT attempt with a bad break-up
- datalog_2019-09-28_09-13T; That the return trip (truncated, from tablet) - at 1602 second there's a sustained WOT with similar results
- Miata342_2019-09-28_10.14.18; This is the "original" tune
- Miata342_2019-09-29_21.54.54; This is the tune after I monkeyed with the VE table