Lack of Power/Sluggish/Spongy/Stumble

DEFINITION
Engine delivers less than expected power. Little or no increase in speed when accelerator pedal is pushed down part way.

PRELIMINARY CHECKS
^ Perform the careful visual / physical checks as described in Preliminary Checks.
^ Compare customer's vehicle to similar unit. Make sure the customer has an actual problem.
^ Remove air filter and check air filter for dirt, or for being plugged. Replace as necessary.

IGNITION SYSTEM CHECKS
^ Knock Sensor (KS) system for excessive spark retard activity. Refer to Chart C-5. Chart C-5 Knock Sensor (KS) System Check
^ Secondary voltage using a spark tester J 26792 (ST 125), or equivalent, to check for a weak coil.
^ Spark advance for excessive retarded ignition timing. Refer to Chart C-5. Chart C-5 Knock Sensor (KS) System Check

ENGNE MECHANICAL CHECKS
^ Engine valve timing and compression.
^ Engine for correct or worn camshaft.

FUEL SYSTEM CHECKS
^ Restricted fuel filter.
^ Fuel pressure, use CHART A-7. Related Tests, Information and Procedures
^ Contaminated fuel.

ADDITIONAL CHECKS
^ Powertrain Control Module (PCM) grounds for being clean, tight and in their proper locations.
^ Torque Converter Clutch for proper operation.
^ Generator output voltage. Repair if less than 9 or more than 16 volts.
^ Exhaust system for possible restriction.
- Inspect exhaust system for damaged or collapsed pipes.
- Inspect muffler for heat distress or possible internal failure.
- For possible plugged three-way converter.