NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [AJ (3.0L Duratec)]


12	Lack/loss of power-acceleration/cruise
DESCRIPTION	• Performance is poor under load (e.g. power down when climbing hills).
POSSIBLE CAUSE	• Improper A/C system operation • Erratic signal or no signal from CMP sensor • Air leakage from intake-air system parts • IMCC malfunction • Purge control solenoid malfunction • EGR valve malfunction • Brake dragging • Erratic signal from CKP sensor • Low engine compression • Vacuum leakage • Poor fuel quality • Spark leakage from ignition coils • 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 (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 - Fuel quality: proper octane, contamination, winter/summer blend • Are all items okay?	Yes	Go to the next step.
1		No	Service as necessary. Repeat Step 1.
2	• Connect WDS or equivalent to 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, TP and VSS 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 intermittent open circuit of MAF sensor and related wire harness. TP PID: • Inspect if TP sensor output increases smoothly. VSS PID: • Inspect for intermittent open circuit of VSS and related wire harness.
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	• Visually inspect the exhaust system part. • Is there any deformed exhaust system part?	Yes	Replace suspected part.
8		No	Go to the next step.
9	• 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.
9		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)].)
10	• Inspect IMCC operation. • Does IMCC work properly?	Yes	Go to the next step.
10	• Inspect IMCC operation. • Does IMCC work properly?	No	Repair or replace malfunctioning part.
11	Note • Following test is for engine stall with A/C on concern. If other symptom exists, go to the next step. • Connect pressure gauge to A/C low and high side pressure lines. • Turn A/C on and measure low side and high side pressures. • Are pressure within specifications?	Yes	Go to the next step.
11		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
12	• Inspect A/C cut-off operation. • Does A/C cut-off work properly?	Yes	Go to the next step.
12		No	Inspect A/C cut-off system components.
13	• 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.
13		No	Go to the next step.
14	• Visually inspect CMP sensor and projections of camshaft pulley. • Are CMP sensor and projections of camshaft pulley okay?	Yes	Go to the next step.
14		No	Replace malfunctioning part.
15	• Inspect EGR system. • Is EGR system okay?	Yes	Go to the next step.
15	• Inspect EGR system. • Is EGR system okay?	No	Replace malfunctioning part.
16	• Is engine compression correct?	Yes	Inspect following: • Valve timing • Internal transaxle components • Brake system for dragging
16	• Is engine compression correct?	No	Inspect for cause.
17	• 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 or reprogram PCM.