Unfortunately, that information is not here:
Lean burn - EcoModder
From what I have read, you often feel something like a misfire, and power output is reduced. I believe it is supposed to burn cooler and if you have an instantaneous gauge it would actually show increased fuel consumption because only the MPGuino measures fuel, everything else measures airflow and does math. I am not sure what else, nor what a code reader could tell you.
I was hoping someone else would step in.