On our rigs is there 2 upstream o2 sensors or just one? I just replaced the downstream and an upstream last night but could only find one upstream sensor (pre-cat).

This upstream sensor was in the exhaust after the manifold junction.

Kind of silly question but after all I've read and done work on other vehicles there is typically two o2 sensors, one for each side of manifold.

Edit: Vehicle does NOT have California Emissions

 

the 4.7 has 4 o2 sensors, the 5.2/5.9 only has 2

 

And California Emmisions model 5.2L and 5.9L has 3.

 

Alright answers my question and confirms what I thought. Thanks