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.
^ Check fuel quality refer to fuel specific gravity check.
^ Check engine oil level and quality.

FUEL SYSTEM
^ CHECK: Fuel supply to injection pump and fuel return from inspection pump.
^ CHECK: For faulty fuel injection nozzles.

ADDITIONAL CHECKS
^ CHECK: Control module grounds for being clean, tight, and in their proper location. Refer to "Component Locations."
^ CHECK: EGR operation for being open or partly open all the time.
^ CHECK: Torque Converter Clutch (TCC) operation. ^ CHECK: A/C operation.
^ 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.