Lack of Power/Sluggish/Spongy/Stumble

DEFINITION
Engine delivers less than expected power. Little or no increase in speed, when accelerator pedal is partially applied.

PRELIMINARY CHECKS
^ Refer to Important Preliminary Checks. Testing and Inspection
^ Compare customers vehicle with a similar unit. Make sure the customer has an actual problem.
^ Remove air filter and check for dirt, or for air ducts being plugged clean or, replace as necessary.
^ Transmission shift pattern and down shift operation Refer to Functional Test Procedure/Transmission Control Systems. Testing and Inspection
^ Check fuel quality refer to fuel specific gravity check in Fuel Systems.
^ Check engine oil level and quality.

FUEL SYSTEM
^ CHECK: Fuel supply to injection pump and fuel return from inspection pump. Refer to Fuel Systems. Fuel Supply Line
^ CHECK: For faulty fuel injection nozzles. Refer to Fuel System. Testing and Inspection

EXHAUST SYSTEM
^ CHECK: For restricted exhaust system. Refer to C-Charts / Restricted Exhaust System Check. Testing and Inspection

TURBO CHARGER
^ CHECK: For air leakage or restriction in air inlet ducts or intake manifold.
^ CHECK: For worn or damaged turbo charger turbine wheel, shaft or compressor wheel.

ADDITIONAL CHECKS
^ CHECK: Control module grounds for being clean, tight, and in their proper location. Refer to Diagrams/Electrical. Diagrams
^ CHECK: EGR operation for being open or partly open all the time. Refer to Exhaust Gas Recirculation (EGR). Testing and Inspection
^ CHECK: Torque Converter Clutch (TCC) operation. Refer to Transmission Control Systems. Testing and Inspection
^ CHECK: A/C operation. Refer to Diagnostic Charts.
^ CHECK: Generator output voltage. Repair if less than 9 or more than 16 volts.

ENGINE MECHANICAL
^ CHECK: Engine compression, valve timing, and for proper or worn camshaft. Refer to Engine/System Diagnosis.