Lack of Power/Sluggish/Spongy/Stumble

Definition

The engine delivers less than expected power. There is little or no increase in speed when partially applying the accelerator pedal.

Preliminary Checks

^ Refer to "Important Preliminary Checks." Testing and Inspection

^ Compare the customer's vehicle with a similar unit. Make sure the customer has an actual problem.

^ Remove the air filter and check for dirt, or for being plugged.

^ Check the transmission shift pattern and down shift operation.

^ Check for fuel injector. Refer to Fuel Injector Coil Test/Fuel Injector Balance Test Procedure.

Fuel System Checks

^ Check for a restricted fuel filter, contaminated fuel or improper fuel pressure. Refer to "Table A-7B." Related Tests, Information and Procedures

^ Check for contaminated fuel.

Ignition System Checks

^ Check for the proper ignition voltage output with the spark tester J 26792 or equivalent.

^ Check the ignition timing and proper operation of the ignition control system.

Exhaust System Checks

^ Check the exhaust system for a possible restriction.

^ Inspect the exhaust system for damaged or collapsed pipes. Inspect the muffler for heat distress or a possible internal failure.

Additional Checks

^ Check the PCM grounds for being clean, tight, and in their proper location.

^ Check the Exhaust Gas Recirculation (EGR) Valve for being open or partly open all the time.

^ Check the generator output voltage.

Engine Mechanical Check

^ Check the engine for the following:

- Compression

- Valve timing

- Proper or worn camshaft