I tried searching the forum for the answer to this question but could not find it. I recently purchased a 2001 Trans am LS1 engine pullout with transmission and what i thought would be all the sensors I needed. There appears to be only one oxygen sensor and it is on the driver side exhaust manifold. There is no space for one on the passenger side manifold. My question is, will I need another oxygen sensor to run. Does the 2001+ year LS1's use two O2 sensors for closed loop operation.

 

Yes, you need one for each bank. There are four total, two after the manifolds and two after the cats.