'95 Grand AM 4cyl has a problem at start up from cold. After two to three
minutes the idle will stumble and then go high several times. Some times it
will die some times it will recover. It will run fine until the next cold
start. This is worse in colder whether. According to the scan tool it
happens just after the computer goes from open loop to closed loop.
I am thinking that this happens too soon for the O2 sensor to be properly
Does any one know what tells the computer to switch to closed loop?
What should the voltage be for a cold O2 sensor?