Apparently, I had something other than over fueling going on. With laptop on passenger seat running ProTune, within a couple of blocks, the O2 readings were beginning to look strange. After several blocks, the front sensor went to 0.00 and stayed there. Suspecting the Deutsche connector, I hit the contacts with DeoxIT D5, cycled the connector a few times, and tried again. No change. I wouldn't have thought a lambda sensor would die with 6,400 miles on it but it is, I presume, 6 years old. Naturally, I have active trouble code P0170, front adaptive max. What I don't know is a lot. I don't know whether to expect a high O2 voltage reading or a low reading with a failed sensor. I don't know if there are multiple failure modes likely or possible.
