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 "Visual and Physical Checks" as described 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.

IGNITION SYSTEM
CHECK: Proper ignition voltage output with J 26792 or equivalent.
CHECK: Proper operation of Electronic Spark Advance (ESA).

EXHAUST SYSTEM
CHECK: Exhaust system for possible restriction. Inspect exhaust system for damaged or collapsed pipes. Inspect muffler for heat distress or possible internal failure.

ENGINE MECHANICAL
CHECK: Engine compression.
CHECK: Engine valve timing.
CHECK: Engine for proper or worn camshaft.

ADDITIONAL CHECKS
CHECK: ECM grounds for being clean, tight, and in their proper location.
CHECK: EGR system operation for being open or partly open, all the time.
CHECK: A/C operation. A/C compressor clutch should cut out at Wide Open Throttle (WOT).
CHECK: Generator output voltage.