Chevrolet 1993 S-10 Pickup Owner's Manual page 72

Featurns & Controls
I
If you have a manual transmission, you have a SHIFT light. This light will
show you when to shift to the next higher gear for best fuel economy.
When this light comes on, you can "shift to the n-ext higher gear i f weather,
road and traffic conditions let you. For the best fuel economy, accelerate
slowly and shift when the light comes on.
While you .accelerate, it is normal for the light to go on and off if you quickly
change the position of the accelerator. Ignore the SHIFT light when you
downshift.
For Four-wheel Drive Vehicles Only: I f your vehicle has four-wheel drive
and is equipped with a manual transmission, disregard the shift light when the
transfer case is in 4 LOW.
Shift Speeds-Manual Transmissions
I f your speed drops below 20 mph (32 km/h), or if the engine is not running
smoothly, you should downshift to the next lower gear. You may have to
downshift two or more gears to keep the engine running smoothly or for good
performance.
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