I noticed today that my Commanded Lambda seems to have drifted down over time and different tunes. Currently it's at .95 at idle and .89 at light load and/or highway cruising.
Isn't it supposed to be at 1.00 on closed loop all the time? I thought that this was programmed into the ECU and not adjustable?
I'm nowhere near WOT or high enough load to be influenced by the PE table. Looking back at some old logs and tunes, it looks like it stared out at 1.00 then drifted down to .95 and now is at .89 much of the time. Adding a new tune doesn't appear to change this. Long term fuel trims are at zero.
Any thoughts?
Thanks!