oxygen sensor
 

The Check Engine light is on; did the the gas pedal trick and got a 1221 error code for bad oxygen sensor. Before I order any parts; just wanted to make sure that there is only one sensor and ask if there are any tricks to replacing it. Any advice would be appreciated. I plan on ordering the removal tool to make things easier.

Thanks

Depending on your model you could have up to 4 O2 sensors. Get penetrating oil and and the sensor tool.

It is a '95 325i with 89,000 miles. Will Bentley tell me how many? Is there any way to narrow down which one it is, if there are this many?

According to Bentley you have one, on the Y right in front of the cats.

Thanks! Only having to replace one is definitely cheaper and easier.