I have a 1993 cutlass supreme convertible internaional with an idle problem.I scanned it,that told me egr,iac and o2 sensor.I have replaced egr and iac,the problem idle is better but it still dies when sitting at a stoplight when I go to takeoff. Now I am not getting any codes but the scann tool indicates my IC bypass is always on.Any ideas? I have replaced plugs ,wires af,EGR,and the IAC.Soon I may even bring it to someone else.