i think my oxygen senser on the turbo hot side might be bad , does anyone know of a test like a olh meter test or something, this senser is almost 400.00 from the dealer, my 9 is running very lean 16/1 at idle ,is this senser tied into the maf to change a/f ratio ??, i have checked everything else boost leak , vacume leak , even changed the a/f ratio senser, i unplug this oxygen senser while the car is idling and theres no change in ratio and still idles the same , please help

 

first question is are you getting a cel?..and did you pull the code? lets assume you did...if the o2 is bad then replace it.
OK bank 1 is the front o2 sensor which monitors and provides the readings for low rpm. If bank 1 o2 is bad you will have a lean idle and a rougher idle as well..car might even stall. Gas milage will be slightly affected too...those are the symptoms of bad bank 1..and strangly enough I have a bad bank 1 o2.. Oh yes and at freeway speed my afr's don't change much, mine are @ 14.5 and don't move much. Basically you will get funny readings.

 

The front O2 sensor is what the engine uses to calibrate the amount of fuel going into the engine. The second O2 sensor is to make sure the CAT is still working, and only a CAT efficiency monitor. We only have B1S1 and B1S2 O2 sensors (bank1sensor1) (bank1sensor2)

O2 sensors work on a .4 to .8 volt range. if your sensor is running under .4 volts or about 1 volt, I'll guarantee you it's bad.

To check it, get a couple small pins and backprobe the sensor wires at the plug. There are four wires, ...they are O2 heater (12v) O2 heater ground (-) O2 signal and O2 ground. You can figure which ones are which by using a DVOM and tagging the different wires. A narrow band O2 sensor switches from .4 to .8 very rapidly, faster than your DVOM can keep up with, so if you have a "range" function, you can use that to see what the MIN, MAX, and MEAN are. You should get a min close to .4 max close to .8 and and a mean of about .6

Hope this helps