Smog test

I have a 1998 toyota altezza rs200 (same as lexus is200 but better engine). The car failed the exhaust emissions text as follows:

Low Idle (860rpm): CO = 7.32 vol% (fail), HC = 0 ppm (n/a)

High Idle (2910 rpm): Lambda = 0.853 (fail), CO = 5.29 vol% (fail) and HC = 224 ppm (fail)

From this informaion can you advise me what might be wrong with the engine, I'm thinking the air flow meter might be problematic, what do you think? Much appreciated.?