Lack of Power, Sluggish

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 at start of Diagnosis By Symptom.

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

^ Remove air filter and check air filter for dirt, or for being plugged. Replace as necessary.


FUEL SYSTEM

^ CHECK: Restricted fuel filter.

^ CHECK: Fuel pressure, use CHART A-7.

^ CHECK: Contaminated fuel.

^ CHECK: Fuel injectors are correct for the vehicle.


IGNITION SYSTEM

^ CHECK: Ignition timing, using "Scan tool".

^ CHECK: Knock sensor system for excessive spark retard activity. Refer to CHART C-5. Use "Scan tool".

^ CHECK: Secondary voltage using an oscilloscope or a spark tester J 26792 (ST-125), or equivalent, to check for a weak coil.

ADDITIONAL CHECKS

^ CHECK: Engine control module grounds for being clean, tight and in their proper locations. See engine control module wiring diagrams.

^ CHECK: Exhaust gas recirculation operation for being open or partly open all the time.

- Refer to CHART C-7.

^ CHECK: Generator output voltage. Repair if less than 9 or more than 16 volts.

^ CHECK: Exhaust system for possible restriction. Refer to CHART B-1.

- Inspect exhaust system for damaged or collapsed pipes.

- Inspect muffler for heat damage or possible internal failure.

^ CHECK: Torque converter clutch for proper operation. Refer to AUTOMATIC TRANSMISSION.


ENGINE MECHANICAL

^ CHECK: Engine valve timing and compression.

^ CHECK: Engine for correct or worn camshaft.