NO.8 ENGINE RUNS ROUGH/ROLLING IDLE[AJ (3.0L Duratec)]

• 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 the following: ― External fuel shut off or accessory (kill switch, alarm etc.) ― Fuel quality: proper octane, contamination, winter/summer blend ― No air leakage from intake-air system ― Proper sealing of intake manifold and components attached to intake manifold: EGR valve, IAC solenoid valve ― Ignition wiring ― Electrical connections ― Fuses ― 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 M-MDS 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 appropriate DTC test.
3	• Is the engine overheating?	Yes	Go to symptom troubleshooting “No.17 Cooling system concerns — Overheating”.
No	Go to the next step.
4	Note • Following test is for engine running rough idle with A/C on concerns. If other symptoms exist, go to the next step. • Connect the pressure gauge to the A/C low and high pressure side lines. • Start the engine and run it at idle. • Turn the A/C switch on. • Measure the low side and high side pressures. • Are reading pressures within specification?	Yes	Go to the next step.
No	If the A/C is always on, go to symptom troubleshooting “No.24 A/C always on or A/C compressor runs continuously”. For other symptoms, Inspect the following: • Refrigerant charging amount • Condenser fan operation
5	Note • Following test is for engine running rough with P/S on. If other symptoms exist, go to the next step. • Start the engine and run it at idle. • Access the PSP PID. • Inspect if the PSP PID is ON while turning steering wheel right to left. • Is the PSP PID normal?	Yes	Inspect the PSP switch operation and wiring harness between PSP switch connector and PCM connector terminal 31.
No	Go to the next step.
6	• Visually inspect CKP sensor and teeth of crankshaft pulley. • Are CKP sensor and teeth of crankshaft pulley normal?	Yes	Go to the next step.
No	Replace the malfunctioning part.
7	• Inspect the ignition coils. • Are ignition coils normal?	Yes	Repair or replace the ignition coil.
No	Go to the next step.
8	• 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 injector. Spark plug is grayish white: • Inspect for clogged fuel injector.
No	Install spark plugs on original cylinders. Go to the next step.
9	• Start the engine and disconnect IAC solenoid valve connector. • Does rpm drop or engine stall?	Yes	Go to the next step.
No	Inspect the IAC solenoid valve and wiring harness.
10	• Install fuel pressure gauge to fuel line. • Start the engine and run it at idle. • Measure the fuel line pressure at idle. • Is the fuel line pressure correct at idle? (See FUEL LINE PRESSURE INSPECTION[AJ (3.0L Duratec)])	Yes	Go to the next step.
No	Zero or low: Inspect the fuel pump, fuel pump stop switch and fuel pump relay related circuit. Inspect for 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)].)
11	• Visually inspect for fuel leakage at fuel injector, O-ring, and fuel line. • Service if necessary. • Does fuel line pressure hold after key is turned to OFF?	Yes	Go to the next step.
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)].)
12	• Connect the M-MDS to the DLC–2. • Start the engine and run it at idle. • Access the LONGFT1 and LONGFT2 PID. • Measure the LONGFT1 and LONGFT2 PID at idle. • Is the PID value within -15%—+15%?	Yes	Go to the next step.
No	LONGFT1 and LONGFT2 PID is out of specification. Below specification (too rich): • Inspect the EVAP control system. ― If the system is normal, go to Step 14. Above specification (too lean): • Inspect for air leakage at intake-air system components. ― If the system normal, go to the next step.
13	• Disconnect the vacuum hose between purge solenoid valve and intake manifold from purge solenoid valve side. • Plug opening end of vacuum hose. • Start the engine. • Does the engine condition improve?	Yes	Inspect if the purge solenoid valve sticks open mechanically. Inspect the EVAP control system.
No	Go to the next step.
14	• Remove and shake PCV valve. • Does PCV valve rattle?	Yes	Go to the next step.
No	Replace the PCV valve.
15	• Is there any deformed exhaust system part?	Yes	Replace the suspected part.
No	Go to the next step.
16	• Visually inspect CMP sensor and tooth of camshaft. • Are CMP sensor and tooth of camshaft normal?	Yes	Go to the next step.
No	Replace the malfunctioning part.
17	• Inspect the engine condition while tapping EGR valve housing. • Does the engine condition improve?	Yes	Replace the EGR valve.
No	Go to the next step.
18	• Is the engine compression correct?	Yes	Inspect the valve timing.
No	Inspect for causes.
19	• Verify the test results. ― If normal, return to the 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 the PCM.

STEP

INSPECTION

RESULTS

ACTION

• Verify the following:

― External fuel shut off or accessory (kill switch, alarm etc.)

― Fuel quality: proper octane, contamination, winter/summer blend

― No air leakage from intake-air system

― Proper sealing of intake manifold and components attached to intake manifold: EGR valve, IAC solenoid valve

― Ignition wiring

― Electrical connections

― Fuses

― Smooth operation of throttle valve

• Are all items normal?

Yes

Go to the next step.

Service if necessary.

Repeat Step 1.

• Connect the M-MDS 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.

DTC is displayed:

• Go to the appropriate DTC test.

• Is the engine overheating?

Yes

Go to symptom troubleshooting “No.17 Cooling system concerns — Overheating”.

Go to the next step.

Note

• Following test is for engine running rough idle with A/C on concerns. If other symptoms exist, go to the next step.

• Connect the pressure gauge to the A/C low and high pressure side lines.

• Start the engine and run it at idle.

• Turn the A/C switch on.

• Measure the low side and high side pressures.

• Are reading pressures within specification?

Yes

Go to the next step.

If the A/C is always on, go to symptom troubleshooting “No.24 A/C always on or A/C compressor runs continuously”.

For other symptoms, Inspect the following:

• Refrigerant charging amount

• Condenser fan operation

Note

• Following test is for engine running rough with P/S on. If other symptoms exist, go to the next step.

• Start the engine and run it at idle.

• Access the PSP PID.

• Inspect if the PSP PID is ON while turning steering wheel right to left.

• Is the PSP PID normal?

Yes

Inspect the PSP switch operation and wiring harness between PSP switch connector and PCM connector terminal 31.

Go to the next step.

• Visually inspect CKP sensor and teeth of crankshaft pulley.

• Are CKP sensor and teeth of crankshaft pulley normal?

Yes

Go to the next step.

Replace the malfunctioning part.

• Inspect the ignition coils.

• Are ignition coils normal?

Yes

Repair or replace the ignition coil.

Go to the next step.

• 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 injector.

Spark plug is grayish white:

• Inspect for clogged fuel injector.

Install spark plugs on original cylinders.

Go to the next step.

• Start the engine and disconnect IAC solenoid valve connector.

• Does rpm drop or engine stall?

Yes

Go to the next step.

Inspect the IAC solenoid valve and wiring harness.

• Install fuel pressure gauge to fuel line.

• Start the engine and run it at idle.

• Measure the fuel line pressure at idle.

• Is the fuel line pressure correct at idle?

(See FUEL LINE PRESSURE INSPECTION[AJ (3.0L Duratec)])

Yes

Go to the next step.

Zero or low:

Inspect the fuel pump, fuel pump stop switch and fuel pump relay related circuit.

Inspect for 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)].)

• Visually inspect for fuel leakage at fuel injector, O-ring, and fuel line.

• Service if necessary.

• Does fuel line pressure hold after key is turned to OFF?

Yes

Go to the next step.

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)].)

• Connect the M-MDS to the DLC–2.

• Start the engine and run it at idle.

• Access the LONGFT1 and LONGFT2 PID.

• Measure the LONGFT1 and LONGFT2 PID at idle.

• Is the PID value within -15%—+15%?

Yes

Go to the next step.

LONGFT1 and LONGFT2 PID is out of specification.

Below specification (too rich):

• Inspect the EVAP control system.

― If the system is normal, go to Step 14.

Above specification (too lean):

• Inspect for air leakage at intake-air system components.

― If the system normal, go to the next step.

• Disconnect the vacuum hose between purge solenoid valve and intake manifold from purge solenoid valve side.

• Plug opening end of vacuum hose.

• Start the engine.

• Does the engine condition improve?

Yes

Inspect if the purge solenoid valve sticks open mechanically.

Inspect the EVAP control system.

Go to the next step.

• Remove and shake PCV valve.

• Does PCV valve rattle?

Yes

Go to the next step.

Replace the PCV valve.

• Is there any deformed exhaust system part?

Yes

Replace the suspected part.

Go to the next step.

• Visually inspect CMP sensor and tooth of camshaft.

• Are CMP sensor and tooth of camshaft normal?

Yes

Go to the next step.

Replace the malfunctioning part.

• Inspect the engine condition while tapping EGR valve housing.

• Does the engine condition improve?

Yes

Replace the EGR valve.

Go to the next step.

• Is the engine compression correct?

Yes

Inspect the valve timing.

Inspect for causes.

• Verify the test results.

― If normal, return to the 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 the PCM.

8	Engine runs rough/rolling idle
DESCRIPTION	• The engine speed fluctuates between the specified idle speed and a lower speed, and the engine shakes excessively. • The idle speed is too slow and the engine shakes excessively.
POSSIBLE CAUSE	• Air leakage from intake-air system parts • A/C system improper operation • Ignition system malfunction • Purge solenoid valve malfunction • IAC solenoid valve improper operation • EGR valve malfunction • Erratic or no signal from CMP sensor • Low engine compression • Erratic signal from CKP sensor • Poor fuel quality • PCV valve malfunction • Air cleaner restriction • Restriction in exhaust system • Disconnected electrical connectors • Inadequate fuel pressure • Fuel pump mechanical malfunction • Fuel leakage from fuel injector • Fuel injector clogging • Engine overheating • Vacuum leakage 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)].)