NO.11 ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE, SURGES [AJ] (VIN: JMZ LW19J7*# 300001-, JM0 LW10J300 300001-301405, JM6 LW10J300 300001-, JM8 LW28J**# 300001-301513)


BME010300103216

11

Engine stalls/quits-acceleration/cruise

Engine runs rough-acceleration/cruise

Misses-acceleration/cruise

Buck/jerk-acceleration/cruise/deceleration

Hesitation/stumble-acceleration

Surges-acceleration/cruise

DESCRIPTION

• Engine stops unexpectedly at beginning of acceleration or during acceleration.
• Engine stops unexpectedly while cruising.
• Engine speed fluctuates during acceleration or cruising.
• Engine misses during acceleration or cruising.
• Vehicle bucks/jerks during acceleration, cruising or deceleration.
• Momentary pause at beginning of acceleration or during acceleration
• Momentary minor irregularity in engine output

POSSIBLE CAUSE

• A/C system improper operation
• Erratic signal or no signal from CMP sensor
• Air leakage from intake-air system parts
• Purge solenoid valve malfunction
• IAC valve improper operation
• EGR valve malfunction
• Erratic signal from CKP sensor
• Low engine compression
• Vacuum leakage
• Poor fuel quality
• Spark leakage from high-tension leads
• Air cleaner restriction
• PCV valve malfunction
• Improper valve timing due to jumping out of timing belt
• Restriction in exhaust system
• Intermittent open or short in fuel pump circuit
• Inadequate fuel pressure
• Fuel pump mechanical malfunction
• Fuel leakage from fuel injector
• Fuel injector clogging
• Intermittent open or short of MAF sensor, TP sensor and VSS
• ATX malfunction
Warning
• The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services:
- Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel.
- Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual.
(See BEFORE SERVICE PRECAUTION [AJ].)
(See AFTER SERVICE PRECAUTION [AJ].)

Diagnostic procedure

STEP

INSPECTION

ACTION

1
• Verify the following:
- Vacuum connection
- Air cleaner element
- No air leakage from intake-air system
- No restriction of intake-air system
- Proper sealing of intake manifold and components attached to intake manifold: EGR valve, IAC valve
- Ignition wiring
- Fuel quality: proper octane, contamination, winter/summer blend
- Electrical connections
- Smooth operation of throttle valve
• Are all items normal?
Yes
Go to the next step.
No
Service if necessary.
Repeat Step 1.
2
• Connect the WDS or equivalent to the DLC-2.
• Turn the ignition switch to the ON position (Engine off).
• Retrieve any DTCs.
• Is "PASSED" displayed?
Yes
No DTC is displayed:
• Go to the next step.
No
DTC is displayed:
• Go to the applicable DTC inspection.
3
• Is the engine overheating?
Yes
Go to symptom troubleshooting "No.17 Cooling system concerns-Overheating".
No
Go to the next step.
4
• Connect the WDS or equivalent to the DLC-2.
• Access RPM, MAF and TP PIDs.
• Drive the vehicle with monitoring PIDs.
• Are PIDs within specification?
Yes
Go to the next step.
No
RPM PID:
• Inspect the CKP sensor and the related wiring harness for vibration and/or intermittent open/short circuit.
MAF PID:
• Inspect for open circuit of the MAF sensor and the related wiring harness intermittently.
TP PID:
• Inspect if output signal from the TP sensor changes smoothly.
VSS PID:
• Inspect for open circuit of the VSS and the related wiring harness intermittently.
5
• Visually inspect the CKP sensor and teeth of the crankshaft pulley.
• Are the CKP sensor and teeth of the crankshaft pulley normal?
Yes
Go to the next step.
No
Replace the malfunctioning part.
6
• Inspect the spark plug conditions.
• Is the spark plug wet, covered with carbon or grayish white?
Yes
Spark plug is wet or covered with carbon:
• Inspect for fuel leakage from the fuel injector.
Spark plug is grayish white:
• Inspect for the clogged fuel injector.
No
Install the spark plugs on original cylinders.
Go to the next step.
7
• Remove and shake the PCV valve.
• Does the PCV valve rattle?
Yes
Go to the next step.
No
Replace the PCV valve.
8
• Inspect that the throttle lever is resting on the throttle valve stop screw and/or the throttle valve orifice plug.
• Is the lever in correct position?
Yes
Go to the next step.
No
Replace the throttle valve body.
9
• Inspect for restriction in the exhaust system.
• Is there any restriction?
Yes
Inspect the exhaust system.
No
Go to the next step.
10
• Install a fuel pressure gauge between the pulsation damper and the fuel distributor.
• Connect a jumper wire between F/P terminal at DLC in the engine compartment and GND.
• Turn the ignition switch to the ON position (Engine off).
• Is the fuel line pressure correct with the ignition switch at the ON position?
Yes
Go to the next step.
No
Zero or low:
• Inspect the fuel pump circuit.
• Inspect for open fuel pump relief valve.
• Inspect for fuel leakage inside the pressure regulator.
• Inspect for the clogged main fuel line.
High:
• Inspect the pressure regulator for high pressure cause.
• Inspect for clogged fuel return line.
11
• Visually inspect for fuel leakage at the fuel injector O-ring and fuel line.
• Service if necessary.
• Does fuel line pressure hold after the ignition switch is turned off?
Yes
Go to the next step.
No
Inspect the pressure regulator diaphragm condition.
• If condition is normal, inspect the fuel injector.
• If condition is not normal, replace the pressure regulator.
12
Note
• The following test is for the engine stall with the A/C on. If other symptom exists, go to the next step.
• Connect a pressure gauge to A/C low and high pressure side lines.
• Turn the A/C on and measure low side and high side pressures.
• Are pressures within the specifications?
Yes
Go to the next step.
No
If the A/C is always on, go to symptom troubleshooting "No.24 A/C always on/A/C compressor runs continuously".
For other symptoms, inspect the following:
• Refrigerant charging amount
• Condenser fan operation
13
Note
• The following test is performed for symptom with the cruise control on. If other symptom exists, go to the next step.
• Inspect the cruise control system.
• Is the cruise control system normal?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part.
14
• Disconnect vacuum hose between the purge solenoid valve and the intake manifold from the purge solenoid valve side.
• Plug opening end of vacuum hose.
• Drive the vehicle.
• Does the engine condition improve?
Yes
Inspect if the purge solenoid valve is stuck open mechanically.
Inspect the EVAP control system.
No
Go to the next step.
15
• Visually inspect the CMP sensor and projections of the camshaft pulley.
• Are the CMP sensor and projections of the camshaft pulley normal?
Yes
Go to the next step.
No
Replace the malfunctioning part.
16
• Inspect the EGR system.
• Is the EGR system normal?
Yes
Go to the next step.
No
Replace the malfunctioning part.
17
• Is the engine compression correct?
Yes
Inspect the following:
• Valve timing
• Internal transaxle part
No
Inspect for cause.
18
• Verify test results.
- If normal, return to diagnostic index to service any additional symptoms.
- If malfunction remains, inspect related Service Information and perform repair or diagnosis.
• If vehicle is repaired, troubleshooting completed.
• If vehicle is not repaired or additional diagnostic information is not available, replace or reprogram the PCM.