How many O2 sensors do I have?
Working on my 91 s10 Blazer, 4.3 4x4. Looking at Advance Auto's web site, they say I have two, an upstream and downstream.Downstream waseasy to get, down on the Y pipe. I assumed I could see the upstream sensor, in the manifold. When I went to remove it, I realized I had the wrong one, I think it is the coolant temp sensor over there, on the passengerside.
Sonow I'm not sure there is a secondo2 sensor, Haynes and Chilton only mention the one. So if there is only one, which should I put in there, upstream or downstream? I assume downstream, because it plug fits. But we can all see how fas assuming anything has got me. I appreciate any help you guys have to offer.
Thanks for checking me out.
91 S10 Blazer 4.3 4WD
89 S10 Blazer 2.8 4WD 5 speed