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 And Physical Checks" in Preliminary Checks. Testing and Inspection
- Compare customer's vehicle to similar unit. Make sure the customer has an actual problem.
- Remove Air Cleaner (ACL) and check for dirt, or for being plugged. Replace as necessary.
- Check PCV valve system for proper operation by placing finger over inlet hole in valve end several times with the engine idling. PCV valve should snap back. If not, check PCV valve hose for blockage or deterioration and replace if necessary. If PCV valve still fails this test, replace it with the correct part number PCV valve.

FUEL SYSTEM
- Check for contaminated fuel.
- Check for restricted fuel filter, contaminated fuel or improper fuel pressure.
- Check fuel pressure.

Refer to Chart A-7B Fuel Pressure Check. Chart A-7B Fuel System Pressure Check

Also refer to On-Board Diagnostic System Check. Testing and Inspection

IGNITION SYSTEM
- Check for proper ignition voltage output with J 26792 or equivalent.
- Check for proper operation of Electronic Spark Advance (ESA). Refer to Ignition System / Description and Operation. Description and Operation

EXHAUST SYSTEM
- Check exhaust system for possible restriction. Inspect exhaust system for damaged or collapsed pipes. Inspect muffler for distress or possible internal failure.

ENGINE MECHANICAL
Check engine for compression, valve timing, proper or worn camshaft. Refer to Engine / System Diagnosis. Engine

ADDITIONAL CHECKS
- Check ECM grounds for being clean, tight, and in their proper locations.
- Check EGR system operation for being open or partly open, all the time, refer to Chart C-7A EGR System Check. Chart C-7A Exhaust Gas Recirculation (EGR) Check
- Check Torque Converter Clutch (TCC) operation. Refer to Chart C-8A Torque Converter Clutch (TCC) Relay System Check. Chart C-8A Torque Converter Clutch (TCC) Relay System Check
- Check A/C operation.
- Check generator output voltage.
- Check TP Sensor for mis-adjustment. Refer to Throttle Position Sensor / Adjustments. Adjustments