hey guys had the car tuned up

and its not good news, as u no ive had a problem with the car loosing revs etc, well i found a way of setting the car up so it didnt, only problem being the co2 levels are at 8%, not good, anyone got any ideas as to why the car holds revs when the co2 level is high but not when its normal??it gets even worse if i have the heating on, dunno if this has anything to do with it??
help plz
