Lack Of Power, Sluggishness, Or Sponginess
Checks 
 | Action 
 | 
DEFINITION: The engine delivers less than expected power. There is little or
no increase in speed when partially applying the accelerator pedal. 
 | 
Preliminary Checks 
 | 
|     •  | Compare the customers vehicle with a similar unit in order to determine
if the customer has an actual problem. |  
  
|     •  | Remove the air filter element and check for dirt or restrictions. |  
  
|     •  | Check the air inlet duct for any blockage or restrictions. |  
  
|     •  | Check the transmission shift pattern and down-shift operation. |  
  
 | 
Sensor/System 
 | Inspect the mass air flow (MAF) sensor operation. Run the engine to normal operating
temperature. Turn OFF all accessories and observe the MAF sensor at idle with a scan
tool. If the MAF sensor reading is more than 3.5 g/s refer to 
DTC P0101
 . 
 | 
Fuel System Checks 
 | 
|     •  | Check for a restricted fuel filter or incorrect fuel pressure. |  
  
|     •  | Check the fuel injectors. Perform the following procedures:  |  
  
 | 
Ignition System Checks 
 | 
|     •  | Check for the proper ignition voltage output with a 
J 26792 
 Spark Tester. |  
  
|     •  | Inspect the spark plugs for correct operation and good ignition system
performance. Refer to 
Spark Plug Inspection
. |  
  
|     •  | Check the knock sensor (KS) and the sensor circuit shielding. A faulty
knock sensor or signal interference could cause excessive retard of the ignition timing
advance. Observe the spark parameter on a scan tool and compare with a known good
vehicle. A typical value at 98 km/h (60 mph) with all engine accessories
off is 26-32 degrees. |  
  
 | 
Exhaust System Checks 
 | 
|     •  | Check the exhaust system for a possible restriction. Refer to 
Restricted Exhaust
 in Engine Exhaust. |  
  
|     •  | Inspect the exhaust system for damaged or collapsed pipes. Inspect the
muffler for heat distress or a possible internal failure. |  
  
 | 
Engine Mechanical Check 
 | 
|     •  | Check for any of the following engine mechanical problems: |  
  
|        -  | An incorrect valve timing |  
  
|        -  | An incorrect or worn camshaft |  
  
 | 
Additional Checks 
 | 
|     •  | If the loss of power is great above 6,000 RPM, inspect for the
correct operation of the Rocker Arm Oil Control system. Refer to 
DTC P2647
. |  
  
|     •  | If there is a slight loss of power at wide open throttle (WOT), inspect
for the correct operation of the Auxiliary Intake Air Control system. Refer to 
Auxiliary Intake Air System Diagnosis
. |  
  
|     •  | Check the powertrain control module (PCM) grounds for being clean, tight,
and in the proper locations. Refer to 
Engine Controls Schematics
. |  
  
|     •  | Check the generator output voltage. |  
  
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