Hesitation, Sag, Stumble
Checks
| Action
|
DEFINITION: Momentary
lack of response as the accelerator is pushed down. Can occur at any
vehicle speed. Usually more pronounced when first trying to make the
vehicle move, as from a stop sign. May cause the engine to stall
if severe enough.
|
Preliminary
|
| • | Search for service bulletins. |
|
Sensor/System
|
| • | Check for proper operation of the TP sensor. |
| • | Check for proper operation of the ECT sensor. |
| • | Check the Oxygen sensor (O2S 1). The O2S 1 should respond quickly
to different throttle positions. If not, check the O2S 1 for silicon or
other contaminants from fuel or the use of improper RTV sealant.
The sensor may have a white powdery coating. Silicon contamination
causes a high but false O2S 1 signal voltage (rich exhaust indication).
The PCM will reduce the amount of fuel delivered to the engine,
causing a severe driveability problem. Refer to Oxygen sensor in
Information Sensors/Switches Description
. |
|
Fuel System
|
| • | Check items which can cause an engine to run rich (long term fuel
trim is significantly in the negative range). Refer to Diagnostic Aids for
DTC P0172 Fuel Trim System Rich
. |
| • | Check items that can cause an engine to run lean (long term fuel
trim is significantly in the positive range). Refer to Diagnostic Aids for
DTC P0171 Fuel Trim System Lean
. |
|
Ignition System
|
| • | Check for proper ignition voltage output with the J 36012-A
spark plug jumper wires and J 26792
spark tester or equivalent. |
| • | Check the spark plugs for the following conditions: |
| - | Check for wet or fuel fouled spark plugs. |
| - | Check for cracks on the spark plugs. |
| - | Check for improper spark plug gap. |
| - | Check for burned electrodes or heavy deposits. |
| • | If the spark plugs are fuel or oil fouled, the cause of the fouling
must be determined before replacing the spark plugs. |
| • | Check the Ignition Control Module (ICM) for proper ground connection. |
| • | Check the ignition coils for cracks or carbon tracking. |
|
Additional Checks
|
| • | Check for proper operation of the Automatic Transaxle. Refer to
Road Test
for 4T40 or
Road Test
for 3T40 in Automatic Transmission. |
| • | Check the generator output voltage. Repair the generator if the
output voltage is less than 11 volts or more than 16 volts. |
| • | 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. |
|
