NO.11 ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE, SURGES [AJ (3.0L Duratec)]


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 • Ignition system malfunction • Air cleaner restriction • PCV valve malfunction • Fuel vapor vent 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 • Inertia fuel pump stop switch malfunction • 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 (3.0L Duratec)].) (See AFTER SERVICE PRECAUTION [AJ (3.0L Duratec)].)


STEP	INSPECTION	RESULTS	ACTION
1	• Verify 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 okay?	Yes	Go to the next step.
1		No	Service as necessary. Repeat Step 1.
2	• Connect WDS or equivalent DLC-2. • Turn key to ON (Engine OFF). • Retrieve any DTCs. • Is "PASSED" displayed?	Yes	No DTC is displayed: • Go to the next step.
2		No	DTC is displayed: • Go to appropriate DTC test.
3	• Is engine overheating?	Yes	Go to symptom troubleshooting "No.17 Cooling system concerns-Overheating".
3	• Is engine overheating?	No	Go to the next step.
4	• Connect WDS or equivalent to DLC-2. • Access RPM, MAF and TP PIDs. • Drive vehicle with monitoring PIDs. • Are PIDs within specification?	Yes	Go to the next step.
4		No	RPM PID: • Inspect CKP sensor and related harness for vibration and/or intermittent open/short circuit. MAF PID: • Inspect for open circuit of MAF sensor and related wire harness intermittently. TP PID: • Inspect if output signal from TP sensor changes smoothly. VSS PID: • Inspect for open circuit of VSS and related wire harness intermittently.
5	• Visually inspect CKP sensor and teeth of crankshaft pulley. • Are CKP sensor and teeth of crankshaft pulley okay?	Yes	Go to the next step.
5		No	Replace malfunctioning part.
6	• Inspect spark plug conditions. • Is spark plug wet, covered with carbon or grayish white?	Yes	Spark plug is wet or covered with carbon: • Inspect for fuel leakage from fuel injector. Spark plug is grayish white: • Inspect for clogged fuel injector.
6		No	Install spark plugs on original cylinders. Go to the next step.
7	• Remove and shake PCV valve. • Does PCV valve rattle?	Yes	Go to the next step.
7	• Remove and shake PCV valve. • Does PCV valve rattle?	No	Replace PCV valve.
8	• Inspect that throttle lever is resting on throttle valve stop screw and/or throttle valve orifice plug. • Is lever in correct position?	Yes	Go to the next step.
8		No	Replace throttle valve body.
9	• Visually inspect the exhaust system part. • Is there any deformed exhaust system part?	Yes	Replace suspected part.
9		No	Go to the next step.
10	• Inspect the inertia fuel pump stop switch. (See FUEL PUMP STOP SWITCH INSPECTION [AJ (3.0L Duratec)].) • Is the IFS switch okay?	Yes	Go to the next step.
10		No	Replace the IFS switch.
11	• Install the fuel pressure gauge to fuel line. • Connect the WDS or equivalent to DLC-2. • Turn the fuel pump on using FP PID in output state control of datalogger function. • Is the fuel line pressure correct? (See FUEL LINE PRESSURE INSPECTION [AJ (3.0L Duratec)].)	Yes	Go to the next step.
11		No	Zero or low: Inspect clogged fuel line. • If normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [AJ (3.0L Duratec)].) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [AJ (3.0L Duratec)].)
12	• Visually inspect for fuel leakage at fuel injector O-ring and fuel line. • Service as necessary. • Does fuel line pressure hold after FP PID is turned OFF? (See FUEL LINE PRESSURE INSPECTION [AJ (3.0L Duratec)])	Yes	Go to the next step.
12		No	Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [AJ (3.0L Duratec)].) • If the fuel injector is normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [AJ (3.0L Duratec)].)
13	Note • Following test is for engine stall with 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 A/C on and measure low side and high side pressures. • Are pressures within specifications?	Yes	Go to the next step.
13		No	If A/C is always on, go to symptom troubleshooting "No.24 A/C always on/A/C compressor runs continuously". For other symptoms, inspect following: • Refrigerant charging amount • Condenser fan operation
14	Note • Following test is performed for symptom with cruise control on. If other symptom exists, go to the next step. • Inspect cruise control system. • Is cruise control system okay?	Yes	Go to the next step.
14		No	Repair or replace malfunctioning part.
15	• Disconnect vacuum hose between purge solenoid valve and intake manifold from purge solenoid valve side. • Plug opening end of vacuum hose. • Drive vehicle. • Does engine condition improve?	Yes	Inspect if purge solenoid valve is stuck open mechanically. Inspect EVAP control system.
15		No	Go to the next step.
16	• Visually inspect CMP sensor and projections of camshaft pulley. • Are CMP sensor and projections of camshaft pulley okay?	Yes	Go to the next step.
16		No	Replace malfunctioning parts.
17	• Inspect EGR system. • Is EGR system okay?	Yes	Go to the next step.
17	• Inspect EGR system. • Is EGR system okay?	No	Replace malfunctioning parts.
18	• Is engine compression correct?	Yes	Inspect following: • Valve timing • Internal transaxle part • Fuel vapor vent valve
18	• Is engine compression correct?	No	Inspect for cause.
19	• Verify test results. - If okay, 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 PCM.