It's on the throttle body, opposite side of the throttle cable.
After the catalytic converter.
It might be in the diagram of parts and places, if comes with it.
Need to know which engine the 02 S10 has.
The 02 Chevy S10 with a 4 cylinder or a 6 cylinder does not have a timing belt.
try lmctruck.com all S10 2 wheel drives are the same from 82 to 02
Three altogether. Two upstream and one down stream.
Don't know what year you have but on a 02 S10 4.3L engine it is located on the drivers side of the engine between spark plugs #3 & #5.
The engine holds 4 and one half qts. of motor oil with filter change.
Could be a plugged fuel filter or a plugged catalytic converter.
The #4 cylinder on a 4.3 L engine would be the middle one on the passenger side.
I had the same problem with my 02. had to replace the EGR Valve.
The throttle position sensor is mounted to the throttle body. It is located opposite of where the throttle cable goes onto the throttle body.