6E–283 ENGINE DRIVEABILITY AND EMISSIONS
Cuts Out, Misses Symptom
StepNo Ye s Va l u e ( s ) Action
101. Visually/physically inspect for the following
conditions:
Restricted air intake system. Check for a
possible collapsed air intake duct, restricted
air filter element, or foreign objects blocking
the air intake system.
Throttle body. Check for objects blocking the
IAC passage or throttle bore, excessive
deposits in the IAC passage and on the IAC
pintle, and excessive deposits in the throttle
bore and on the throttle plate.
Large vacuum leak. Check for a condition that
causes a large vacuum leak, such as an
incorrectly installed or faulty PCV valve or
brake booster hose disconnected .
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 8
11Check the injector connections. If any of the injectors
are connected to an incorrect cylinder, correct as
necessary.
Was a problem found?
—Verify repairGo to Step 12
121. Perform the “Injector Coil/Balance Test” in Fuel
Metering System
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 13
131. Check for fuel in the pressure regulator vacuum
hose.
2. If fuel is present, replace the fuel pressure regulator
assembly. Refer to
Fuel Metering System.
3. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 14
141. Check for proper ignition voltage output with spark
tester J 26792 (ST-125). Refer to
Electronic Ignition
System
for the procedure.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 15
151. 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 16
161. 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 17
6E–285 ENGINE DRIVEABILITY AND EMISSIONS
Hesitation, Sag, Stumble Symptom
StepActionVa l u e ( s )Ye sNo
1DEFINITION:
Momentary lack of response as the accelerator is
pushed down. Can occur at any vehicle speed. Usually
most pronounced when first trying to make the vehicle
move, as from a stop sign. May cause the engine to stall
if severe enough.
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. Check 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 5
51. 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 6
6Observe the TP angle display on Tech 2 while slowly
increasing throttle pedal.
Does the TP angle display steadily increase from 0% at
closed throttle to 100% at WOT?
—Go to Step 7Go to Step 18
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?
—Verify repairGo to Step 10
91. Check items that can cause the engine to run lean.
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
6E–288
ENGINE DRIVEABILITY AND EMISSIONS
Default Matrix Table
Service Procedure Default Strategy
A referral strategy has been established to assist the
technician with additional information when the cause of
the failure cannot be determined. If no problem is found
after performing diagnostics, then refer to the default
matrix table for further diagnostic information.
Default Matrix Table
Strategy Based Diagnostic Charts
Initial DiagnosisDefault Section(s)
On-Board Diagnostic (OBD) System
CheckVehicle does not enter diagnostics.Chassis Electrical
On-Board Diagnostic (OBD) System
CheckVehicle enters diagnostics and
communicates with Tech 2. MIL is
“ON” in diagnostics. Engine does not
start and run.Ignition System Check
On-Board Diagnostic (OBD) System
CheckEngine starts and runs, no PCM
codes set. Customer complains of
vibration.—
On-Board Diagnostic (OBD) System
CheckEngine starts and runs, no PCM
codes set. Customer complains of
harsh or soft shift, poor performance,
delayed or no engagement into drive
or reverse, transmission fluid leak,
transmission noise or vibration, or
improper TCC operation.Automatic Transmission
PCM Power and Ground CheckOn-Board Diagnostic (OBD) System
Check.Chassis Electrical
PCM Power and Ground CheckOn-Board Diagnostic (OBD) System
Check. PCM power and ground
circuits OK. Data link voltage
incorrect.Chassis Electrical
On-Board Diagnostic (OBD) System
CheckEngine starts and runs, no PCM
codes set. Customer complains of
harsh or soft shift, poor performance,
delayed or no engagement into drive
or reverse, transmission fluid leak,
transmission noise or vibration, or
improper TCC operation.Automatic Transmission
SymptomsInitial DiagnosisDefault Section(s)
Intermittents1. On-board Diagnostic (OBD)
system check.
2. Careful visual/physical
inspections.Chassis Electrical
Hard Starts1. OBD system check.
2. Sensors (ECT, MAP, MAF, TP) ;
MAP output chart.
3. Fuel system electrical test, fuel
system diagnosis.
4. Ignition system.
5. IAC system check.Engine Mechanical, Ignition
System Check, Exhaust System
Diagnosis
Surges and/or Chuggles1. OBD system check.
2. Heated oxygen sensors.
3. Fuel system diagnosis.
4. Ignition system.Calibration ID “Broadcast
Code”/Service Bulletins, Ignition
System Check, Generator
Output, Exhaust System
Diagnosis, 4L30-E System Test
6E–289 ENGINE DRIVEABILITY AND EMISSIONS
Symptoms Default Section(s)Initial Diagnosis
Lack of Power, Sluggish or Spongy1. OBD system check.
2. Fuel system diagnosis.
3. Ignition system.
4. Knock sensor.
5. EGR operation.
6. EGR system check.Refer to Exhaust System in
Engine Exhaust, TCC Operation,
Calibration ID/Service Bulletins
Detonation/Spark Knock1. OBD system check.
2. Transmission range switch.
3. EGR operation.
4. EGR system check.
5. TCC operation.
6. Fuel system diagnosis.
7. Ignition system.
8. Knock sensor.TCC operation, Cooling System,
Ignition System Check,
Calibration ID/Service Bulletins
Hesitation, Sag, Stumble1. OBD system check.
2. TP.
3. MAP output check.
4. Fuel system diagnosis.
5. Fuel injector and fuel injector
balance test.
6. Ignition system.EGR Operation, EGR System
Check, Generator Output
Voltage (refer to
Chassis
Electrical
), Calibration ID/Service
Bulletins, Ignition System Check
Cuts Out, Misses1. OBD system check.
2. Cylinder balance test.Ignition System Check
Rough, Unstable, or Incorrect Idle,
Stalling1. OBD system check.
2. Fuel injector and fuel injector
balance test.
3. Ignition system.
4. IAC operation.
5. EGR operation.MAP Output Check, Throttle
Linkage, IAC System Check,
EGR System Check, A/C Clutch
Control Circuit Diagnosis,
Crankcase Ventilation System,
Calibration ID/Service Bulletins,
Generator Output Voltage (refer
to
Chassis Electrical), Exhaust
Diagnosis
Poor Fuel Economy1. OBD system check.
2. Careful visual/physical inspection.
3. Ignition system.
4. Cooling system.TCC Operation, Exhaust System
(refer to
Engine Exhaust)
Engine Cranks But Will Not Run1. OBD system check.Fuel System Electrical
Diagnosis, Fuel System
Diagnosis, Fuel Injector and Fuel
Injector Balance Test.
Excessive Exhaust Emissions or
Odors1. OBD system check.
2. Emission test.
3. Cooling system.
4. Fuel system diagnosis.
5. Fuel injector and fuel injector
balance test.
6. Crankcase ventilation system.
7. Ignition system.
8. MAP output check.EGR System Check, Exhaust
Diagnosis, Calibration ID/Service
Bulletins
Dieseling, Run-On1. OBD system check.
2. Careful visual/physical inspection.
3. Fuel system diagnosis.—
6E–290
ENGINE DRIVEABILITY AND EMISSIONS
Symptoms Default Section(s)Initial Diagnosis
Backfire1. OBD system check.
2. Ignition system.
3. Fuel system diagnosis.
4. Fuel injector and fuel injector
balance test.
5. EGR operation, EGR system
check.Exhaust System Diagnosis,
Intake Casting Flash, Ignition
System Check
Catalyst Monitor1. OBD system check.
2. Careful visual/physical inspection.
3. Heated oxygen sensors.Exhaust System
Fuel Trim1. OBD system check.
2. Careful visual/physical inspection.
3. Fuel system diagnosis.
4. Heated oxygen sensors, MAF
sensors.Exhaust System Intake Air
System
Evaporative Emissions1. OBD system check.
2. Careful visual/physical inspection.
3. Fuel system diagnosis.—
Heated Oxygen Sensors1. OBD system check.
2. Careful visual/physical inspection.Exhaust System
6E–292
ENGINE DRIVEABILITY AND EMISSIONS
Crankshaft Position (CKP)
Sensor
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the electrical connector to the CKP
sensor.
3. Remove one bolt and the CKP sensor from the right
side of the engine block, just behind the mount.
NOTE: Use caution to avoid any hot oil that might drip
out.
TS22909
Inspection Procedure
1. Inspect the sensor O-ring for cracks or leaks.
2. Replace the O-ring if it is worn or damaged.
3. Lubricate the new O-ring with engine oil.
4. Install the lubricated O-ring.
Installation Procedure
1. Install the CKP sensor in the engine block.
2. Install the CKP sensor mounting bolt.
Tighten
Tighten the mounting bolt to 9 Nꞏm (78 lb in.).
TS22909
3. Connect the electrical connector to the CKP sensor.
4. Connect the negative battery cable.
Engine Coolant Temperature
(ECT) Sensor
Removal Procedure
NOTE: Care must be taken when handling the engine
coolant temperature (ECT) sensor. Damage to the ECT
sensor will affect proper operation of the fuel injection
system.
1. Disconnect the negative battery cable.
2. Drain the radiator coolant. Refer to
Draining and
Refilling Cooling System
in Engine Cooling.
3. Disconnect the electrical connector.
014RW127
6E–310
ENGINE DRIVEABILITY AND EMISSIONS
Pedal Stroke Adjustment Procedure
1. Loosen the jam nut and rotate the kick-down switch
counterclockwise.
TS24039
2. Fully depress the pedal and hold it by hand. Rotate
the switch clockwise until the switch clicks.
3. Rotate the switch 1/2 turn further and lock it in this
position by tightening the jam nut.
TS24040
4. Step on the accelerator pedal and make sure there is
a clicking sound at the full-stroke position.
Fuel Filter Cap
General Description
The fuel filler cap includes a vacuum valve and a pressure
valve.If high vacuum or high pressure occurs in the fuel tank,
each valve works to adjust the pressure in order to
prevent damage to the tank at the EGR valve.
TS23767
Inspection Procedure
NOTE: Replace the fuel filler cap with the same type of
filler cap that was originally installed on the vehicle.
Check the seal ring in the filler cap for any abnormality
and for seal condition.
Replace the filler cap if any abnormality is found.
Fuel Filter
Removal Procedure
1. Disconnect the negative battery cable.
2. Remove the fuel filler cap.
041RW005
6E–311 ENGINE DRIVEABILITY AND EMISSIONS
3. Disconnect the fuel line from the fuel filter on the
engine side.
4. Disconnect the fuel line from the fuel filter on the fuel
tank side.
041RW006
5. Remove the bolt on the fuel filter holder.
041RW007
6. Remove the fuel filter.
041RW008
Inspection Procedure
1. Replace the fuel filter when the following occur:
Fuel leaks from the fuel filter body.
The fuel filter body is damaged.
The fuel filter is clogged with dirt or sediment.
2. If the drain hole is clogged, clean the drain.
041RW009