Lack of Power, Sluggishness or Sponginess
Checks 
 | Action 
 | 
DEFINITION: The engine delivers less than expected power. There is little
or no increase in the speed  when           the accelerator pedal is pushed
 down part way. 
 | 
Preliminary Checks 
 | 
|     •  | Search for the service bulletins. |  
  
|     •  | Compare the customer's vehicle to a similar vehicle. Ensure that
the customer's vehicle has an actual problem. |  
  
|     •  | Inspect the air cleaner filter for dirt or being plugged. |  
  
 | 
Fuel
System Checks 
 | 
|     •  | Inspect the items which can cause an engine to run rich, where
long term fuel trim  is significantly in the negative range. Refer to Diagnostic
 Aids for 
DTC P0172 
    . |  
  
|     •  | Inspect the items that can cause an engine to run lean, where
long term fuel trim is significantly in the positive range. Refer to Diagnostic
Aids  for 
DTC P0171 
    . |  
  
 | 
Sensor/System 
 | 
|     •  | Use a scan tool in order to monitor the knock system (KS) system
for excessive spark retard activity. Refer to 
DTC P0325 
  . |  
  
|     •  | Ensure proper operation of the manifold absolute pressure (MAP)
sensor. |  
  
|     •  | Ensure proper operation of the throttle position (TP) sensor. |  
  
|     •  | Inspect  for a restricted air intake system. |  
  
 | 
Ignition
System 
 | 
|     •  | Ensure proper ignition voltage output with the J 26792 
 Spark Tester or equivalent. |  
  
|     •  | Inspect  the spark plugs for the following conditions: |  
  
|        -  | Wet or fuel-fouled spark plugs |  
  
|        -  | Cracks on the spark plugs |  
  
|        -  | Improper spark plug gap |  
  
|        -  | Burned electrodes or heavy deposits |  
  
|     •  | If the spark plugs are fuel or oil-fouled, determine the cause
of the fouling  before replacing the spark plugs. |  
  
|     •  | Inspect  the ignition control module (ICM) for proper ground connection. |  
  
|     •  | Inspect  the ignition coils for cracks or carbon tracking. |  
  
|     •  | Inspect  the spark plug wires for proper resistance and condition. |  
  
 | 
Engine
Mechanical 
 | 
|     •  | Inspect  the engine for the following engine mechanical problems: |  
  
|        -  | A leaking cylinder head gasket |  
  
|        -  | A worn or an incorrect camshaft |  
  
 | 
Additional
Checks 
 | 
|     •  | Inspect  the exhaust system for a possible restriction: |  
  
|        -  | Inspect the exhaust system for damaged or for possible collapsed
pipes. |  
  
|        -  | Inspect the muffler for heat distress or for possible internal
failure. |  
  
|        -  | Inspect  for a possible plugged three-way catalytic converter
(TWC). Refer to 
Restricted Exhaust 
in Engine Exhaust. |  
  
|     •  | Inspect  the vacuum lines for kinks or for leaks. |  
  
|     •  | Inspect  the generator output voltage. Repair the generator if
the output voltage is less than 11 volts, or more than 16 volts. |  
  
|     •  | Inspect  the air conditioning (A/C) system operation. The A/C
clutch should cut out at the wide open throttle (WOT) position. |  
  
|     •  | If all procedures have been completed and no malfunctions have
been found, review and inspect the following items: |  
  
|        -  | All electrical connections within the suspected circuit and/or
systems. |  
  
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