Hesitation, Sag, Stumble
Checks
| Action
|
DEFINITION: A momentary lack of response when the accelerator is pushed
down. The condition can occur at any vehicle speed. The condition
is usually more pronounced when the driver first attempts to make
the vehicle move, such as acceleration from a stop sign. The condition
may cause the engine to stall if severe enough.
|
Preliminary
|
| • | Search for service bulletins. |
|
Sensor/System
| Check for
the following conditions:
| • | Proper operation of the manifold absolute pressure (MAP) sensor.
Refer to
DTC P0105
. |
| • | Proper operation of the throttle position (TP) sensor. Refer to
DTC P0105
. |
| • | Proper operation of the engine coolant temperature (ECT) sensor.
Refer to
DTC P0117
and
DTC P0118
. |
| • | Check the oxygen sensor (O2S 1). The O2S 1 should
quickly respond to the different throttle positions. If the sensor does not,
check the O2S 1 for silicon, or for other contaminants
from the fuel or from the use of an improper RTV sealant. The sensor
may have a white powdery coating. Silicon contamination causes
a high but false O2S 1 signal voltage, indicating a rich
exhaust indication. The powertrain control module (PCM) will reduce
the amount of fuel delivered to the engine, causing a severe
driveability problem. |
|
Fuel
System
| Check
for the following conditions:
| • | Conditions which can cause an engine to run rich, indicating that
the long term fuel trim is significantly in the negative range. Refer to Diagnostic
Aids for
DTC P0172
. |
| • | Conditions that can cause an engine to run lean, indicating that
the long term fuel trim is significantly in the positive range. Refer to Diagnostic
Aids for
DTC P0171
. |
|
Ignition
System
| Check
for the following conditions:
| • | Proper ignition voltage output--Use the J 36012-A
Ignition System Diagnostic Harness
and use the 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. |
| • | The ignition control module (ICM) for proper ground connection |
| • | The ignition coils for cracks or for carbon tracking |
|
Additional
Checks
| Check
for the following conditions:
| • | Proper operation of the automatic transaxle. Refer to
Road Test
in Automatic Transmission 4T40-E/4T45-E. |
| • | The generator output voltage--Repair the generator if the
output voltage is less than 11 volts, or more than 16 volts. |
| • | If you have completed all of the procedures, and if you have found
no malfunctions, review the following items: |
| - | Inspect all electrical connections within the suspected circuit
and/or systems. |
|
