Bear with me on this please, ive not used the tables provided in the tech resourses much, had a CAP car and wanted to see what lambda was on it, entered, CO2 12.5 % CO 2.52 % HC 89 PPM, O2 2.5 %, this gave me a A/F ratio of 15.2 %, my problem is 2.52 % CO is n... Login to read more.