Lack of Power, Sluggish or Spongy
Checks
| Action
|
DEFINITION: The engine delivers less than the expected power. When
the accelerator pedal is pushed part-way down, there is little or
no increase in the speed.
|
Preliminary Checks
|
| • | Search for the service bulletins. |
| • | Check and compare the customer's vehicle to a similar vehicle.
Ensure that the customer's vehicle has an actual problem. |
| • | Check the air cleaner filter for dirt or for restrictions. |
|
Fuel
System Checks
|
| • | Check items which can cause an engine to run rich, where the long
term fuel trim is significantly in the negative range. Refer to Diagnostic
Aids for
DTC P0172
. |
| • | Check for conditions that can cause an engine to run lean, where
the long term fuel trim is significantly in the positive range. Refer to Diagnostic
Aids for
DTC P0171
. |
| • | Check the throttle linkage and the throttle cables in order to
ensure that the throttle plate opens fully. |
|
Sensor/System
|
| • | Use a scan tool in order to monitor the knock sensor (KS) system
for excessive spark retard activity. |
| • | Check for proper operation of the manifold absolute pressure (MAP)
sensor. Refer to
DTC P0105
. |
| • | Check for proper operation of the throttle position (TP) sensor.
Refer to
DTC P0105
. |
| • | Check for proper operation of the oxygen sensor 1 (O2S) 1. |
| • | Check for a restricted air intake system. |
|
Ignition
System
|
| • | Check for proper ignition voltage output with the J 36012-A
Ignition System Diagnostic Harness
and with a J 26792
Spark
Tester or equivalent. |
| • | Check 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 you replace the spark plugs. |
| • | Check the ignition control module (ICM) for proper ground connection. |
| • | Check the ignition coils for cracks or for carbon tracking. |
|
Engine
Mechanical
| Check the engine for the following engine mechanical problems:
|
Additional
Checks
|
| • | Check for proper operation of the transaxle and the torque converter
clutch (TCC). Refer to
Road Test
in Automatic Transmission 4T40-E/4T45-E. |
| • | Check 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. |
| - | Check for possible plugged three-way catalytic converter. Refer
to
Restricted Exhaust
in Engine
Exhaust. |
| • | Check the vacuum lines for kinks or leaks. |
| • | If all procedures have been completed and no malfunctions have
not been found, review and inspect the following items: |
| - | Visually and physically inspect all electrical connections within
the suspected circuit and/or systems. |
|