So, I am troubleshooting a P0171 that came up this past Monday. Toyota said in a bulletin, the air/fuel sensor has a manufacturing defect 2005-2006, so if you get P0171, they recommended changing that sensor.
So, I changed the sensor. Doesn't appear to have been the source of the problem - I think I maybe just need a new air intake gasket. I checked there for leaks previously, but must have missed it, or - the weather change has brought it on. I'm only getting a slight hiccup symptom when its cold out, and the engine has not been run that day. It goes away once the car warms up, and it runs smooth then. The P0171 appeared after about 2 weeks of that symptom showing up, on a Monday morning after not driving all day Sunday.
But in changing the air/fuel ratio sensor, we have this collar on it. And I can't find a way to remove it. It's NY winter, 20 degrees, dark at 4:30pm...this is my only car, and I had work the next day....so yeah I just put the new sensor in without the shield/collar.
Does anyone know how to remove those rings? It looks like its got to be something very simple that I'm just not seeing. I would like to put the shield piece back on with the new sensor.
I'd also like to know any opinions / insights on whether that shield piece is particularly important or vital to the sensor functionality. I suspect its ok, but not kosher, to leave it off.