Engine Poor DRIVEABILITY

ENGINE POOR DRIVEABILITY REFERENCE CHART

7	ENGINE STALLS/QUITS ENGINE RUNS ROUGH MISSES BUCK/JERK HESITATION/STUMBLE ACCELERATION SURGES ROLLING IDLE
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.

ENGINE STALLS/QUITS
ENGINE RUNS ROUGH
MISSES
BUCK/JERK
HESITATION/STUMBLE
ACCELERATION SURGES
ROLLING IDLE

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.

DTC DETECTION CONDITION POSSIBLE COUSES CHART

STEP	INSPECTION		ACTION
1	PRELIMINARY CHECKS Carry out the following preliminary checks: Vacuum lines (routing, integrity). Air filter (restricted). Intake air tubes (leaks, restrictions). Correct sealing of intake manifold and components attached to intake air (such as EGR). Ignition wiring. Fuel quality (concerns such as correct octane, contamination, winter/summer blend, ethanol content in fuel). Electrical connections. Be aware of the over RPM and speed limiting functions of the PCM. Are all checks OK?	Yes	GO to the next step.
1		No	REPAIR as required. VERIFY symptom no longer exists.
2	CHECK FOR STALL AT IDLE (PARK/NEUTRAL) Does engine now stall at idle in PARK/NEUTRAL?	Yes	Engine stalls now. GO to step 5.
2		No	GO to the next step.
3	CHECK FOR ROUGH IDLE (PARK/NEUTRAL) Does engine idle rough in PARK/NEUTRAL?	Yes	Engine idles rough. GO to step 6.
3		No	GO to the next step.
4	CARRY OUT PCM QUICK TEST See PCM QUICK TEST . Are any DTCs displayed during Continuous Memory, Key On Engine Off (KOEO) or Key On Engine Running (KOER) Self-Tests?	Yes	CHECK for cause. See DTC INDEX - PCM .
4		No	GO to step 7.
5	ENGINE STALLS NOW: CARRY OUT PCM KOEO SELF-TEST. Retrieve and record continuous memory DTCs. Carry out KOEO self-test. See PCM QUICK TEST . Are any DTCs displayed?	Yes	CHECK for cause. See DTC INDEX - PCM .
5		No	GO to step 8.
6	ROUGH IDLE: CARRY OUT PCM KOEO SELF-TEST. Retrieve and record continuous memory DTCs. Carry out KOEO self-test. See PCM QUICK TEST . Are any DTCs displayed?	Yes	CHECK for cause. See DTC INDEX - PCM .
6		No	GO to the next step.
7	CHECK PIDs Reconnect IDS or equivalent tester. Check following PIDs. ECT, LONGFT1, LONGFT2, VPWR. See PCM PROGRAMMING - IDS . Are PIDs within specification?	Yes	GO to the next step.
7		No	REPAIR as required.
8	CHECK SECONDARY IGNITION SYSTEM Is a strong blue spark visible at each disconnected high-tension lead while cranking engine?	Yes	CHECK the spark plugs. If OK, GO to the next step. If not OK, CLEAN or INSTALL new spark plugs. See SPARK PLUGS REMOVAL/INSTALLATION - 2.5L or SPARK PLUGS REMOVAL/INSTALLATION - 3.0L .
8		No	CHECK following: High-tension leads. CKP sensor. See CRANKSHAFT POSITION (CKP) SENSOR MALFUNCTION . CMP sensor. See CAMSHAFT POSITION (CMP) SENSOR MALFUNCTION .
9	CHECK FUEL DELIVERY SYSTEM Carry out fuel pressure inspection. See TEST 8: FUEL LINE/FUEL PRESSURE HOLD INSPECTION . Fuel line pressure: 240 - 380 kPa (35 - 55 psi) Is fuel pressure correct?	Yes	GO to the next step.
9		No	If pressure is greater than 380 kPa (55 psi): INSTALL a new fuel pump. See FUEL PUMP MODULE REMOVAL/INSTALLATION . If pressure is less than 240 kPa (35 psi): CHECK fuel supply line for restriction.
10	CHECK FUEL DELIVERY SYSTEM Check fuel pump fuel flow. See TEST 4: FUEL DELIVERY SYSTEM . Did fuel system flow the required amount of fuel?	Yes	CHECK injector for leakage. See TEST 9: FUEL INJECTOR INSPECTION . If injector leaks, See FUEL RAIL REMOVAL/INSTALLATION - 2.5L or FUEL RAIL REMOVAL/INSTALLATION - 3.0L 01-14A-29. If injector OK, GO to the next step.
10		No	CHECK fuel supply line for restriction.
11	CHECK EXHAUST SYSTEM See EXHAUST SYSTEM CONCERNS . Is there a restriction in the exhaust system?	Yes	REPAIR as required.
11		No	For 2.5L engine, GO to the next step. For 3.0L engine, GO to step 13.
12	CHECK PCV SYSTEM Remove PCV valve and shake it. Does PCV valve rattle?	Yes	REINSTALL PCV valve. GO to the next step.
12		No	INSTALL a new PCV valve.
13	CHECK PCV SYSTEM Start engine and bring to normal operating temperature. Disconnect crankcase ventilation hose from throttle body. Place a stiff piece of paper over the hose. Wait 1 minute. Does vacuum hold paper in place?	Yes	GO to the next step.
13		No	DISCONNECT evaporative hose. PLACE a stiff piece of paper over the hose. Wait 1 minute. Does vacuum hold paper in place? If yes, See DTCS P0455 AND P1443: EVAPORATIVE EMISSION (EVAP) SYSTEM MALFUNCTION step 2. If no, CHECK for vacuum leaks, obstructions in the PCV system, oil cap, PCV valve, rocker cover bolt torque/gasket leak. REPAIR as required.
14	CHECK TRANSAXLE (A/T ONLY) If vehicle has manual transaxle, go to the next step. If vehicle has automatic transaxle, see SYMPTOM TROUBLESHOOTING CHART - EXTERNAL CONTROLS for Diagnostic Strategy. Is automatic transaxle OK?	Yes	GO to the next step.
14		No	REPAIR as required.
15	CHECK EVAP SYSTEM Check EVAP system. If symptom is "engine stalls," see CANISTER VENT (CV) SOLENOID MALFUNCTION step 2. For other symptoms, See DTCS P0455 AND P1443: EVAPORATIVE EMISSION (EVAP) SYSTEM MALFUNCTION step 1. Is a fault indicated?	Yes	REPAIR as required.
15		No	GO to the next step.
16	CHECK BASE ENGINE Check engine compression. Is engine compression correct?	Yes	GO to the next step.
16		No	REPAIR as required.
17	CHECK INTAKE AIR SYSTEM Check intake air system (for the following symptoms only: Stalls/quits at idle, runs rough at idle, rolling idle) See LOW IDLE/STALLS DURING DECELERATION . Is a fault indicated?	Yes	REPAIR as required.
17		No	GO to the next step.
18	ADDITIONAL CHECKS Additional checks: Driveline. Transaxle/clutch (M/T). Charging system. A/C system (for surge with A/C on). Cruise control system (for surge with cruise control on). A/C compressor diode (for rolling idle and/or stumble when A/C cycles on). Are the checks OK?	Yes	VERIFY test results. If OK, see DIAGNOSTIC INDEX to REPAIR any additional symptoms.
18		No	REPAIR as required.