1991 GMC Light Duty Truck Fuel, Emissions and Driveability Manual

The 1991 Light Duty Truck Fuel and Emissions Service Manual (X-9136) covers gasoline engines with throttle body injection, 2.5L, 2.8L, 4.3L, 5.0L, 5.7L and 7.4L, in S and T, C and K, R, V and P trucks and M, L and G vans. It replaces sections 6C and 6E of the 1991 light duty truck service manuals and supplements them with system descriptions, diagnosis and on-vehicle service for fuel control and emissions. Sections run from general information and driveability symptoms through Computer Command Control scan-tool diagnosis to the individual emission systems, special tools, abbreviations and an index. Wiring diagrams for the vehicles are in the separate Truck Wiring Diagram booklet.