Chevrolet 1994 Blazer Owner's Manual page 274

Exhaust System
'To help prevent damage to your exhaust system, do not continue to drive
your vehicle if you notice:
Engine misfiring
Loss of performance
0
Other unusual operating conditions
Have your engine and exhaust system serviced regularly.
Three- Way Catalytic Converter
Your vehicle's three-way catalytic converter is designed to reduce the
pollutants in your vehicle's exhaust. Use only unleaded fuel in your vehicle.
If you use leaded fuel, you could damage your three-way catalytic converter
and other engine components.
Engine Control Module System
This system has an oxygen (02) sensor that helps keep your engine's
air-fuel mixture at a proper level. Use only unleaded fuel in your vehicle. If
you use leaded fuel, you could damage your oxygen
(02)
sensor and affect
your vehicle's emissions.
Malfunction Indicator Lamp (SERVICE ENGINE SOON )
This light on your instrument panel lets you know when your emission
system needs service. The light will come on briefly when you start your
engine to let you know that the system is working. If it does not come on
when you start your engine, or if it comes on and stays on while you're
driving, your system may need service. Your vehicle should still be
driveable, but you should have your system serviced right away.
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