Temp sensor for the gauge.
The coolant temp sensor on a 2003 Chevy S10 V6 is located on the front of the intake manifold. To replace simply unscrew the old sensor and screw on the new one.
After the catalytic converter.
A short to ground. Check wiring/sensor for damage.
The IAT sensor is located in the air duct just past the air cleaner box.
its the sensor in the tube going in to the throttle body from the air cleaner
The 1994 S10 uses a MAP sensor, not a MAF sensor. We need to know size engine you have in that S10.
It should be located in the air intake snorkel between the filter box and the throttle body.
Rear of the engine block.
Bank 1, on a 4.3 L engine would be on the drivers side.
The idle sensor on a 1991 S10 4.3 can be located at the engine bay.
I don't believe the 03 S-10 uses an etc (electronic throttle control) sensor.