1994 GMC Jimmy Owner's Manual - Page 274

Exhaust System To help prevent damage to your exhaust system, do not continue to drive your vehicle if notice: you 0 Engine misfiring Loss of performance 0 Other unusual operating conditions Have yourengine and exhaust system serviced regularly. Three- Way Catalytic Converter Your vehicle's three-way catalytic converter is designed reduce the to pollutants in your vehicle's exhaust. Use only unleaded in your vehicle. fuel If you use leaded fuel, could damage your three-way catalytic converter you and otherengine 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 sensor and affect (02) your vehicle's emissions. Malfunction Indicator Lamp (SERVICE ENGINE SOON ) This light on your instrument panel lets know when youremission you 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 come on not when you start your engine, or if it comes on and stays on while you're be driving, your systemmay need service. Your vehicle should still driveable, butyou should have your system serviced right away. 6-38