Something else that is very important, you either use LTFT that has been dialed in, eg run for at least 80km of street driving OR use a wideband and LTFT disabled. You can't use a wideband if you are in closed loop as the ECU will be essentially adjusting the map at zero for you skewing your results.
What I recommend is disable LTFT and set O2 min temp to 4096?F if you are going to use a wideband. Then use wideband_afr / commanded afr to get your fuel trim error.
I wrote some software that helps visualise when you should adjust the map at zero. It will auto filter the data and show you the trend of map vs fuel trim/afr so you can determine if it is a constant error (map slope) or an offset error (map zero)
http://www.hptuners.com/forum/showth...d-density-maps
Here is a link to my spreadsheet that will recalc the offset based on lambda error.
https://dl.dropboxusercontent.com/u/...%20recalc.xlsx