Lack of Power, Sluggish or Spongy
Checks
| Action
|
DEFINITION: Engine
delivers less than expected power. Little or no increase in speed when the
accelerator pedal is pushed down part way.
|
Preliminary Checks
|
• | Verify that the powertrain control module (PCM) grounds are clean,
tight, and in the correct locations. |
• | Remove and check the air filter element for dirt and for restrictions.
Replace the element as necessary. |
|
Fuel System Checks
|
• | Check for a restricted fuel filter. |
• | Check the items that can cause an engine to run rich. |
• | Check the items that can cause an engine to run lean. |
|
Sensor and System Checks
|
• | Using a scan tool, monitor the knock sensor (KS) system for excessive
spark retard activity. |
• | Check the exhaust gas recirculation (EGR) system for correct operation. |
|
Ignition System
| Remove spark plugs and check for the following conditions:
An improper spark plug gap will cause a driveability problem. The spark
plug gapping should be done with a wire gauge gap tool. If the spark
plugs are gas or oil fouled, the cause of the fouling must be determined
before replacing the spark plugs.
• | Check for a loose ignition control module ground. |
• | Check the spark plugs for the correct heat range. |
|
Engine Mechanical
| Check for the following conditions:
• | Any excessive oil in the combustion chambers may indicate leaking
valve seals. Refer to
Oil Consumption Diagnosis
in Engine Mechanical. |
• | Any incorrect basic engine parts--Inspect the following parts: |
Refer to
Symptoms - Engine Mechanical
in Engine Mechanical.
|
Additional Checks
|
• | Check the exhaust system for restrictions. Refer to
Restricted Exhaust
in Engine Exhaust. |
| Check the brake switch assembly of the traction control system . A loss
of performance can result from an incorrectly adjusted or a failed extended
travel brake switch. The PCM operates in the Torque Management mode
when the PCM determines that the brake pedal and the throttle are depressed
at the same time. |
|