Page 4921 of 6000

6E–264
ENGINE DRIVEABILITY AND EMISSIONS
Hard Start Symptom
StepNo Ye s Va l u e ( s ) Action
121. Remove spark plugs. Check for wet plugs, cracks,
wear, improper gap, burned electrodes, or heavy
deposits. Refer to
Electronic Ignition System.
NOTE: If spark plugs are gas or oil fouled, the cause of
the fouling must be determined before replacing the
spark plugs.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 13
131. Check for a loose ignition coil ground.
Refer to
Electronic Ignition System.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 14
141. Remove the ignition coils and check the ignition
coils for cracks or carbon tracking.
2. If a problem is found, replace affected coil(s) as
necessary.
Was a problem found?
—Verify repairGo to Step 15
151. Check IAC operation. Perform the procedure in the
DTC P0506, Step 6 diagnostic table.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 16
161. Check for the following engine mechanical
problems (refer to
Engine Mechanical):
Low compression
Leaking cylinder head gaskets
Worn or incorrect camshaft
Camshaft drive belt slipped or stripped
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 17
171. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:
Visual/physical inspection
Te c h 2 d a t a
Freeze Frame data/Failure Records buffer
All electrical connections within a suspected
circuit and/or system.
3. If a problem is found, repair as necessary.
Was a problem found?
—Verify repair
Contact
Te c h n i c a l
Assistance
Page 4922 of 6000

6E–265 ENGINE DRIVEABILITY AND EMISSIONS
Surges and/or Chuggles Symptom
StepActionVa l u e ( s )Ye sNo
1DEFINITION:
Engine power variation under steady throttle or cruise.
Feels like the vehicle speeds up and slows down with
no change in the accelerator pedal.
Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
—Verify repairGo to Step 3
3Was a visual/physical check performed?
—Go to Step 4
Go to
Visual/Physic
al Check
4Be sure that the driver understands transmission
torque converter clutch and A/C compressor operation
as explained in the owner’s manual.
Inform the customer how the TCC and the A/C clutch
operate.
Is the customer experiencing a normal condition?
—System OKGo to Step 5
51. Check the the fuel control heated oxygen sensors
(HO2S, B1S1 and B2S1). The fuel control heated
oxygen sensors (HO2S) should respond quickly to
different throttle positions. If they don’t, check them
for silicon or other contaminants from fuel or use of
improper RTV sealant. The sensors may have a
white powdery coating.
Silicon contamination causes a high but false
HO2S signal voltage (rich exhaust indication).
The PCM will then reduce the amount of fuel
delivered to the engine, causing a severe
driveability problem. For more information, refer
to
Powertrain Control Module (PCM) and Sensors.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 6
61. Check the fuel pressure. Refer to Fuel System
Pressure Test
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 7
7Monitor the long term fuel trim on Tech 2.
Is the long term fuel trim significantly in the negative
range (rich condition)?
—Go to Step 8Go to Step 9
81. Check items that can cause the engine to run rich.
Refer to
Diagnostic Aids in DTC P0172 Diagnostic
Support
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Go to Step 10Verify repair
91. Check items that can cause the engine to run lean.
Refer to
Diagnostic Aids in DTC P0171.
2. If a problem is found, repair as necessary.
Was a problem found?
—Go to Step 10Verify repair
Page 4923 of 6000

6E–266
ENGINE DRIVEABILITY AND EMISSIONS
Surges and/or Chuggles Symptom
StepNo Ye s Va l u e ( s ) Action
101. Check for proper ignition voltage output with spark
tester J 26792 (ST-125). Refer to
Electric Ignition
System
for procedure.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 11
111. Check for a loose ignition coil ground.
Refer to
Electric Ignition System.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 12
121. Check the ignition coils for cracks or carbon
tracking.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 13
131. Remove the spark plugs and check for wet plugs,
cracks, wear, improper gap, burned electrodes, or
heavy deposits. Refer to
Electronic Ignition
System
.
NOTE: If spark plugs are gas or oil fouled, the cause of
the fouling must be determined before replacing the
spark plugs.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 14
141. Check the injector connections.
2. If any of the injector connectors are connected to an
incorrect cylinder, correct as necessary.
Was a problem found?
—Verify repairGo to Step 15
151. Check PCM grounds for the cleanliness, tightness
and proper locations. Refer to the PCM wiring
diagrams in
Electrical Diagnosis.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 16
161. Check MAF sensor connections.
2. If a problem is found, replace the faulty terminals as
necessary. Refer to
Electrical Diagnosis for wiring
repair procedures.
Was a problem found?
—Verify repairGo to Step 17
171. Visually/physically check vacuum hoses for splits,
kinks, and proper connections and routing as
shown on the “Vehicle Emission Control
Information” label.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 18
Page 4924 of 6000
6E–267 ENGINE DRIVEABILITY AND EMISSIONS
Surges and/or Chuggles Symptom
StepNo Ye s Va l u e ( s ) Action
181. Check the exhaust system for possible restriction:
Inspect the exhaust system for damaged or
collapsed pipes.
Inspect the muffler for heat distress or possible
internal failure.
Check for a possible plugged three-way
catalytic converter by checking the exhaust
system back pressure. Refer to
Restricted
Exhaust System Check
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 19
191. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:
Visual/physical inspection
Te c h 2 d a t a
Freeze Frame data/Failure Records buffer
All electrical connections within a suspected
circuit and/or system.
3. If a problem is found, repair as necessary.
Was a problem found?
—Verify repair
Contact
Te c h n i c a l
Assistance
Page 4925 of 6000

6E–268
ENGINE DRIVEABILITY AND EMISSIONS
Lack of Power, Sluggish or Spongy Symptom
StepActionVa l u e ( s )Ye sNo
1DEFINITION:
Engine delivers less than expected power. Little or no
increase in speed when accelerator pedal is pushed
down part-way.
Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
—Verify repairGo to Step 3
3Was a visual/physical check performed?
—Go to Step 4
Go to
Visual/Physic
al Check
41. Remove and check the air filter element for dirt or
restrictions. Refer to
Air Intake System in
ON-Vehicle Service.
2. Replace the air filter element if necessary.
Was a repair required?
—Verify repairGo to Step 5
51. Check for low fuel pressure. Refer to Fuel System
Pressure Test
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 6
61. Check for water- or alcohol-contaminated fuel.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 7
71. Using Tech 2, monitor the knock sensor (KS)
system for excessive spark retard activity. Refer to
Knock Sensor (KS) System.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 8
81. Check for proper ignition voltage output with spark
tester J 26792 (ST-125). Refer to
Electronic Ignition
System
for procedure.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 9
91. Remove the spark plugs and check for wet plugs,
cracks, wear, improper gap, burned electrodes, or
heavy deposits. Refer to
Electronic Ignition
System
.
NOTE: If spark plugs are gas or oil fouled, the cause of
the fouling must be determined before replacing the
spark plugs.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 10
101. Check the ignition coils for cracks or carbon
tracking.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 11
Page 4926 of 6000

6E–269 ENGINE DRIVEABILITY AND EMISSIONS
Lack of Power, Sluggish or Spongy Symptom
StepNo Ye s Va l u e ( s ) Action
111. Check the PCM grounds for the cleanliness,
tightness and proper locations. Refer to the PCM
wiring diagrams in
Electrical Diagnosis.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 12
121. Check the exhaust system for possible restriction:
Inspect the exhaust system for damaged or
collapsed pipes.
Inspect the muffler for heat distress or possible
internal failure.
Check for a possible plugged three-way
catalytic converter by checking the exhaust
system back pressure. Refer to
Restricted
Exhaust System Check
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 13
131. Check the torque converter clutch (TCC) for proper
operation. Refer to
4L30-E Transmission
Diagnosis
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 14
141. Check for an engine mechanical problem. Check
for low compression, incorrect or worn camshaft,
loose timing belt, etc. Refer to
Engine Mechanical.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 15
151. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:
Visual/physical inspection
Te c h 2 d a t a
Freeze Frame data/Failure Records buffer
All electrical connections within a suspected
circuit and/or system.
3. If a problem is found, repair as necessary.
Was a problem found?
—Verify repair
Contact
Te c h n i c a l
Assistance
Page 4927 of 6000

6E–270
ENGINE DRIVEABILITY AND EMISSIONS
Detonation/Spark Knock Symptom
StepActionVa l u e ( s )Ye sNo
1DEFINITION:
A mild to severe ping, usually worse under acceleration.
The engine makes sharp metallic knocks that change
with throttle opening.
Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
—Verify repairGo to Step 3
3Was a visual/physical check performed?
—Go to Step 4
Go to
Visual/Physic
al Check
4If Tech 2 readings are normal (refer to Ty p i c a l S c a n
Va lu es
) and there are no engine mechanical faults, fill
the fuel tank with a known quality gasoline that has a
minimum octane rating of 87 and re-evaluate the
vehicle performance.
Is detonation present?
—Go to Step 5Verify repair
51. Check the transmission range switch circuit. Use
Tech 2 and be sure Tech 2 indicates that the vehicle
is in drive with the gear selector in drive or overdrive.
2. If a problem is found, diagnose and repair the
transmission range switch as necessary (refer to
4L30-E Automatic Transmission Diagnosis).
Was a problem found?
—Verify repairGo to Step 6
61. Check TCC operation. Refer to 4L30-E
Transmission Diagnosis
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 7
71. Check for obvious overheating problems:
Low engine coolant.
Restricted air flow to radiator, or restricted
water flow through radiator.
Correct coolant solution should be a 50/50 mix
of approved antifreeze/coolant and water.
Refer to
Engine Cooling.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 8
81. Check fuel pressure. Refer to Chart Fuel System
Pressure Test.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 9
91. Check items that can cause an engine to run lean
(long term fuel trim significantly in the positive
range). For a lean condition, refer to
Diagnostic
Aids
in DTC P0171 Diagnostic Support.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 10
Page 4928 of 6000

6E–271 ENGINE DRIVEABILITY AND EMISSIONS
Detonation/Spark Knock Symptom
StepNo Ye s Va l u e ( s ) Action
101. Spark plugs for proper heat range. Refer to General
Information
.
2. If incorrect spark plugs are installed, replace spark
plugs as necessary.
Did any spark plugs require replacement?
—Verify repairGo to Step 11
111. Remove excessive carbon buildup with a top engine
cleaner. Refer to instructions on the top engine
cleaner can.
2. Re-evaluate vehicle performance.
Is detonation still present?
—Go to Step 12Verify repair
121. Check for an engine mechanical problem. Perform
a cylinder compression check. Refer to
Engine
Mechanical
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 13
131. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:
Visual/physical inspection
Te c h 2 d a t a
Freeze Frame data/Failure Records buffer
All electrical connections within a suspected
circuit and/or system.
3. If a problem is found, repair as necessary.
Was a problem found?
—Verify repair
Contact
Te c h n i c a l
Assistance