Chevrolet Repair: 2000 Chevy S-10, O2 Sensor Bank 2, oxygen sensors, vacuum leak

Question
They pulled the diagnostics at a local Auto Zone and it said Sensor 2 bank 1 was coming up lean.  They printed me out a diagram but it's a universal diagram that is for an 8 cylinder.  I called up the shop and they said the same that it's just a standard regular diagram.  I was looking around and all I can see is the O2 sensor on bank 1, the 02 sensor above and below the cat.  I looked around with a drop light and all I see are spark plug boots on that side of the engine.  Is it hidden somewhere that's hard to get to or is it hidden from me right in front of my face?  Thanks for any help in advance.

Answer
Hi Brad,
There may not be any more sensors than you see.
The problem could be something like low fuel pressure,(Filter, pump, or pressure regulator) dirty injectors, or a vacuum leak.
Don't just replace the oxygen sensors without testing for those possibilities.

And clean the EGR valve.

Van