🏷️ Basic Information Identification Make: Chevrolet Model: C/K Year: 1991 Vehicle Type: Full-size Pickup Truck Codes Chassis Code: GMT400 👋 Introduction Market Position Market Positioning: The definitive guide for owners and technicians of the 1991 Chevrolet C/K series trucks, offering dealership-level repair and maintenance expertise. Competitive Analysis Competitive Advantage: This manual provides vehicle-specific information, unlike generic guides, ensuring accuracy and efficiency in diagnostics and repairs. Key Features Key Features Highlight: Directly sourced from manufacturer-provided data, this manual mirrors the information used by authorized Chevrolet service centers. 📋 Manual Details Coverage Areas Coverage: All Models & All Repairs A-Z Page Count Estimated Page Count: 1500+ Manual Type Manual Type: Factory Service Manual (FSM) / Repair Manual Language Language: English Format Format: Printed 📖 Manual Coverage Systems Covered Engine Systems: Engine mechanical, lubrication, cooling, fuel, exhaust, ignition, emissions control Transmission Drivetrain: Manual and automatic transmissions, transfer case (4WD), driveshafts, axles, differentials Brake Systems: Front disc brakes, rear drum brakes, parking brake, hydraulic system, ABS (if equipped) Suspension Steering: Independent front suspension (IFS), leaf spring rear suspension, steering gearbox, power steering system Electrical Electronics: Battery, charging system, starting system, lighting, instrumentation, engine control module (ECM), body electrical, wiring diagrams Body Chassis: Frame, body panels, doors, windows, interior trim, HVAC system, seats, bumpers Procedures Included Diagnostic Procedures: Troubleshooting guides, diagnostic trouble codes (DTCs), symptom-based diagnostics Maintenance Procedures: Fluid changes, filter replacements, tune-ups, lubrication services Repair Procedures: Component removal and installation, overhaul procedures, adjustments Specification Tables: Torque specifications, clearances, fluid capacities, resistance values Technical Depth Depth Of Coverage: Comprehensive (from basic maintenance to complete engine/transmission rebuilds and complex diagnostics) 📊 Manual Specifications File Format File Format: Physical bound book Print Quality Print Quality: High-quality, durable paper with clear text and diagrams Binding Type Binding Type: Sturdy, professional binding for frequent use in a workshop environment Paper Type Paper Type: Glossy or semi-gloss paper for durability and clarity of illustrations ⚙️ Engine Specifications Primary Engine Engine Options: 4.3L V6 (VIN Z, W), 5.0L V8 (VIN E), 5.7L V8 (VIN K), 7.4L V8 (VIN P) Performance Horsepower Range: Approx. 160-230 hp (depending on engine) Torque Range: Approx. 230-370 lb-ft (depending on engine) Fuel System Fuel Delivery: Throttle Body Injection (TBI) or Multi-Port Fuel Injection (MPFI) depending on engine Engine Codes V8 Engine Code K: 5.7L V8 (VIN K) - L05 V8 Engine Code E: 5.0L V8 (VIN E) - L03 V6 Engine Code Z: 4.3L V6 (VIN Z) - LB4 V8 Engine Code P: 7.4L V8 (VIN P) - L19 🔧 Transmission Standard Standard Transmission: 4-speed Manual (NV4500 for some heavy-duty models) Optional Optional Transmission: 4-speed Automatic (700R4/4L60, 4L80E for heavy-duty models) Features 4Wd Transfer Case: New Process 208 (part-time manual shift) or NP241 (part-time electronic shift) Fluid Specifications Automatic Transmission Fluid: Dexron-III ATF (or equivalent) Manual Transmission Fluid: GL-4 Gear Lubricant (specific viscosity varies by model) 📐 Dimensions Exterior Body Styles: Regular Cab, Extended Cab, Crew Cab; Fleetside (bed) and Stepside (bed) Wheelbase Options: 117.5" (std cab), 131.5" (ext cab), 143" (long bed), 155.5" (dually) Weights Gvwr Range: 5,500 - 10,000+ lbs (depending on configuration) Curb Weight Range: 4,000 - 5,500+ lbs (depending on configuration) 🛡️ Safety Features Ratings Safety Ratings: NHTSA ratings for this era are generally lower by modern standards. Consult specific recall data for safety concerns. Active Features Active Safety Features: Anti-lock Braking System (ABS) was optional on some models, particularly rear-wheel anti-lock. Passive Features Passive Safety Features: Seat belts, reinforced safety cage construction. 💡 Technology Features Infotainment Infotainment Features: AM/FM radio with cassette player, optional CD player, manual or power windows and locks, basic climate control. Driver Assistance Driver Assistance Systems: Limited driver assistance features by modern standards. Cruise control was common. Connectivity Connectivity Options: No modern connectivity features like Bluetooth or USB. Analog systems. 🔧 Maintenance Service Intervals Oil Change Interval: Typically 3,000-5,000 miles or 6 months, whichever comes first (consult manual for specific engine recommendations). Tune Up Interval: Spark plugs and filters usually recommended every 30,000-60,000 miles depending on component type and engine. Fluid Specifications Engine Oil Specification: API SF/CD or SG/CD; Viscosity: 5W-30, 10W-30, or 10W-40 depending on ambient temperature (consult manual). Coolant Specification: Ethylene glycol based coolant (e.g., Dex-Cool equivalent for later versions, but typically green conventional coolant for 1991). Brake Fluid Specification: DOT 3 Hydraulic Brake Fluid Known Issues Common Wear Items: Ball joints, tie rod ends, idler/pitman arms (suspension wear), intake manifold gaskets (leaks), catalytic converter (clogging/failure), fuel pump (in-tank). Electrical Gremlins: Dashboard warning lights, HVAC blower motor issues, fuel gauge inaccuracies can occur with age. Engine Specific Concerns: 4.3L V6 (LB4) can develop intake manifold gasket leaks; older 5.0L and 5.7L V8s may experience valve guide wear. Part Numbers Air Filter Example: ACDelco A3021C (example, verify for specific engine) Oil Filter Example: ACDelco PF25 (example, verify for specific engine) 📚 Vehicle History Brand Heritage Chevrolet...