WELL looks like its fueling my co levels are moving up and down like a yoyo it was all set up but still had the problem today i started her up and the fuel is so rich it burns ya eyes so had it redone and it was on 9.8% so was readjusted down after a few reves car cut out and wouldnt start again so he adjusted the screw back and it started again and co was reading -10 so what can be causing the change in the co levels once its been reved a few times the guy didnt have a clue as he cant find any air leaks the vacum on idle is around -8 if thats any help wouldnt it be lower if it was leaking air ? thanks for any help Andy