High NOX low hydrocarbons and low CO2 on a 1993 240 no egr new bosch O2 sensor. Both speeds in smog test read about 3 times the limit and low hydrocarbons and low CO2 like nearly not reading. This to me must be a lean condition in the combustion process. The car has been reading a ritch code when you pull the codes. I am leaning twords a idle speed sensor mass airflow sensor or just replace the cat.