Where are the oxygen sensors on a 1987 GMC Truck?
Where are the oxygen sensors on a 1987 GMC Truck? The 1987 and newer GM trucks use one or more oxygen sensors located along the exhaust. They're not difficult to replace, but they can take some elbow grease and some basic safety equipment to do properly. What are the symptoms of a bad oxygen sensor? 1 An illuminated check-engine light 2 A rough engine idle 3 A misfiring engine 4 Worsening fuel economy 5 Failed emissions inspection What does the crank sensor on a GMC Sierra do? The crank sensor measures engine RPMs and then relays that information to the...