A smog tech told me that my new O² sensor "isn't warming up fast enough," which I term as being complete nonsense. At issue is that the car runs open loop until driven under power for a short time, at which time car goes to closed loop, the solenoid duty cycle closes up a bit and the ESC II system blocks vacuum transducer-caused advance at idle. It evidently provides more advance at idle in open loop to promote better driveability due to fairly lean mixutre when cold provided by the feedback solenoid in the main jet. This guy says that the O² sensor should be fully warmed up and giving signal voltage in three to five minutes after a cold start even at idle; I say he's confused with later, heater-equipped O² sensors. The replacement O² sensor is from Bosch. Comments, especially from smog techs?
By the way, the car passed with nearly the lowest dyno emissions for that model/year in the state's database, so obviously SOMETHING'S right here!