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Symptom Chart - Engine Performance

Symptom Possible Sources Action
Difficult starting Inoperative or damaged ignition system
Air or vacuum leak
Inoperative or damaged fuel system
Inoperative or damaged starting system
Inoperative or damaged VCT oil control solenoid(s)
Refer to the appropriate Engine article for the procedure.
Damaged charging system/ battery REFER to: Charging System .
Burnt valve INSTALL a new cylinder head. REFER to: Cylinder Head 2.3L EcoBoost . or REFER to: Cylinder Head LH 3.0L EcoBoost . REFER to: Cylinder Head RH 3.0L EcoBoost . or REFER to: Cylinder Head LH 3.3L Duratec-V6 - Hybrid . REFER to: Cylinder Head RH 3.3L Duratec-V6 - Hybrid . TEST the system for normal operation after the repair.
Worn piston INSTALL a new piston. TEST the system for normal operation after the repair.
Worn piston rings INSTALL new piston rings. TEST the system for normal operation after the repair.
Worn cylinder INSTALL a new cylinder block. TEST the system for normal operation after the repair.
Damaged head gasket INSTALL a new cylinder head gasket. REFER to: Cylinder Head 2.3L EcoBoost . or REFER to: Cylinder Head LH 3.0L EcoBoost . REFER to: Cylinder Head RH 3.0L EcoBoost . or REFER to: Cylinder Head LH 3.3L Duratec-V6 - Hybrid . REFER to: Cylinder Head RH 3.3L Duratec-V6 - Hybrid . TEST the system for normal operation after the repair.
Inoperative or damaged cooling system Refer to the appropriate Engine article for the procedure.
Fouled spark plugs INSTALL new spark plugs. REFER to: Spark Plugs 2.3L EcoBoost . REFER to: Spark Plugs 3.0L EcoBoost . REFER to: Spark Plugs 3.3L Duratec-V6 . REFER to: Spark Plugs 3.3L Duratec-V6 - Hybrid .
Fail-safe cooling invoked (if equipped) Refer to ENGINE CONTROLS - INTRODUCTION (EXCEPT DIESEL & HYBRID) .
Poor idling Vacuum leaks
Inoperative or damaged EGR system
Inoperative or damaged VCT oil control solenoid(s)
Refer to the appropriate Engine article for the procedure.
Inoperative or damaged ignition system Refer to the appropriate Engine article for the procedure.
Inoperative or damaged cooling system
Inoperative or damaged fuel system
Refer to the appropriate Engine article for the procedure.
Fail-safe cooling invoked (if equipped) Refer to ENGINE CONTROLS - INTRODUCTION (EXCEPT DIESEL & HYBRID) .
Incorrect valve clearance ADJUST valve clearance. Refer to the appropriate Engine article for the procedure. TEST the system for normal operation after the repair.
Incorrect valve-to-valve seat contact INSTALL a new cylinder head. REFER to: Cylinder Head 2.3L EcoBoost . or REFER to: Cylinder Head LH 3.0L EcoBoost . REFER to: Cylinder Head RH 3.0L EcoBoost . or REFER to: Cylinder Head LH 3.3L Duratec-V6 . REFER to: Cylinder Head RH 3.3L Duratec-V6 . TEST the system for normal operation after the repair.
Damaged head gasket INSTALL a new cylinder head gasket. REFER to: Cylinder Head 2.3L EcoBoost . or REFER to: Cylinder Head LH 3.0L EcoBoost . REFER to: Cylinder Head RH 3.0L EcoBoost . or REFER to: Cylinder Head LH 3.3L Duratec-V6 . REFER to: Cylinder Head RH 3.3L Duratec-V6 . TEST the system for normal operation after the repair.
Fouled spark plugs INSTALL new spark plugs. REFER to: Spark Plugs 2.3L EcoBoost . REFER to: Spark Plugs 3.0L EcoBoost . REFER to: Spark Plugs 3.3L Duratec-V6 . REFER to: Spark Plugs 3.3L Duratec-V6 - Hybrid .
Engine runs rough Inoperative or damaged fuel system
Air or vacuum leaks
EGR system fault
Inoperative or damaged cooling system
Inoperative or damaged ignition system
Inoperative or damaged VCT oil control solenoid(s)
Refer to the appropriate Engine article for the procedure.
Fail-safe cooling invoked (if equipped) Refer to ENGINE CONTROLS - INTRODUCTION (EXCEPT DIESEL & HYBRID) .
Burnt or sticking valve INSTALL a new valve. TEST the system for normal operation after the repair.
Weak or broken valve spring INSTALL a new valve spring. TEST the system for normal operation after the repair.
Carbon accumulation in combustion chamber ELIMINATE carbon buildup. TEST the system for normal operation after the repair.
Excessive oil consumption Leaking oil REPAIR oil leakage. TEST the system for normal operation after the repair.
Blocked or restricted turbocharger oil drain pipe INSPECT the turbocharger drain pipe. REPAIR as necessary. TEST the system for normal operation after the repair.
Damaged or collapsed air intake hoses and tubes Tighten hoses clamps. INSPECT for damage and REPAIR as necessary. TEST the system for normal operation after the repair.
Damaged exhaust or exhaust leaks at turbocharger housing or exhaust manifold. INSPECT for leaks. Leaks can be detected audibility or visually, by a discoloration caused by escaping hot exhaust gases. REPAIR as necessary. TEST the system for normal operation after the repair.
Turbocharger oil seals leaking REFER to Turbocharger Internal Oil Leak Test. REFER to: Turbocharger 2.3L EcoBoost . or REFER to: Turbocharger 3.0L EcoBoost . TEST the system for normal operation after the repair.
Inoperative PCV system REPAIR or INSTALL new components as necessary. TEST the system for normal operation after the repair.
Incorrect oil CHANGE oil to correct specification. TEST the system for normal operation after the repair.
Worn valve stem seal INSTALL a new valve stem seal. TEST the system for normal operation after the repair.
Worn valve stem or valve guide INSTALL a new cylinder head. REFER to: Cylinder Head 2.3L EcoBoost . or REFER to: Cylinder Head LH 3.0L EcoBoost . REFER to: Cylinder Head RH 3.0L EcoBoost . or REFER to: Cylinder Head LH 3.3L Duratec-V6 . REFER to: Cylinder Head RH 3.3L Duratec-V6 . TEST the system for normal operation after the repair.
Sticking piston rings INSTALL new piston rings. TEST the system for normal operation after the repair.
Worn piston ring groove
Missing or damaged oil control ring
INSTALL a new piston and piston pin. TEST the system for normal operation after the repair.
Worn piston or cylinder INSTALL a new piston or cylinder block. TEST the system for normal operation after the repair.
Oil in coolant Leaking head gasket
Damaged cylinder block
Damaged cylinder head
INSPECT the engine components. INSTALL new engine components as necessary. Refer to the appropriate Engine article for the procedure. TEST the system for normal operation after the repair.
Leaking oil cooler INSPECT the oil cooler and seal for damage. INSTALL new components as necessary. REFER to: Oil Cooler 2.3L EcoBoost . or REFER to: Oil Cooler 3.0L EcoBoost . or REFER to: Oil Cooler 3.3L Duratec-V6 . or REFER to: Oil Cooler 3.3L Duratec-V6 - Hybrid . Refer to the appropriate Engine article for the procedure.
Coolant in oil Leaking head gasket
Damaged cylinder block
Damaged cylinder head
INSPECT the engine components. INSTALL new engine components as necessary. Refer to the appropriate Engine article for the procedure. TEST the system for normal operation after the repair.
Insufficient power Inoperative or damaged ignition system
Air intake system blockage
Lubrication system blockage
Inoperative or damaged fuel system
Inoperative or damaged TB (throttle body)
Refer to the appropriate Engine article for the procedure.
Turbocharger turbine or compressor wheel damage INSPECT the turbocharger. REFER to the Check for Free Rotation-- On Vehicle. REFER to: Turbocharger 3.0L EcoBoost . or REFER to: Turbocharger 2.3L EcoBoost . . TEST the system for normal operation after the repair.
Damaged exhaust or exhaust leaks at turbocharger housing or exhaust manifold INSPECT for leaks. Leaks can be detected audibility or visually, by a discoloration caused by escaping hot exhaust gases. REPAIR as necessary. TEST the system for normal operation after the repair.
Malfunctioning turbocharger bypass valve Refer to ENGINE CONTROLS - INTRODUCTION (EXCEPT DIESEL & HYBRID) .
Oil level too high DRAIN oil to correct level.
Incorrect engine oil INSTALL correct specification engine oil. TEST the system for normal operation after the repair.
Excessive accessory drive belt loading
Inoperative or damaged cooling system
REFER to: Accessory Drive Belt 2.3L EcoBoost . or REFER to: Accessory Drive Belt 3.0L EcoBoost . . Cooling system : REFER to: Engine Cooling 2.3L EcoBoost . or REFER to: Engine Cooling 3.0L EcoBoost . or REFER to: Engine Cooling 3.3L Duratec-V6 . or REFER to: Engine Cooling 3.3L Duratec-V6 - Hybrid .
Fail-safe cooling invoked (if equipped) Refer to ENGINE CONTROLS - INTRODUCTION (EXCEPT DIESEL & HYBRID) .
Damaged or plugged exhaust system INSPECT exhaust system. TEST the system for normal operation after the repair.
Incorrect tire size REFER to: Identification Codes .
Dragging brakes REFER to: Brake System .
Slipping transmission Refer to the appropriate Automatic Transmission article for the procedure.
Slipping clutch Refer to the appropriate Manual Transmission article for the procedure.
Incorrect valve clearance ADJUST valve clearance. Refer to the appropriate Engine article for the procedure. TEST the system for normal operation after the repair.
Worn or damaged valve tappet INSTALL a new valve tappet. TEST the system for normal operation after the repair.
Damaged valve guide
Compression leakage at valve seat
Seized valve stem
INSTALL a new cylinder head assembly. REFER to: Cylinder Head 2.3L EcoBoost . or REFER to: Cylinder Head LH 3.0L EcoBoost . REFER to: Cylinder Head RH 3.0L EcoBoost . or REFER to: Cylinder Head LH 3.3L Duratec-V6 . REFER to: Cylinder Head RH 3.3L Duratec-V6 . TEST the system for normal operation after the repair.
Weak or broken valve spring INSTALL a new valve spring. TEST the system for normal operation after the repair.
Worn or damaged cam INSTALL a new camshaft. TEST the system for normal operation after the repair.
Damaged head gasket INSTALL a new head gasket. REFER to: Cylinder Head 2.3L EcoBoost . or REFER to: Cylinder Head LH 3.0L EcoBoost . REFER to: Cylinder Head RH 3.0L EcoBoost . or REFER to: Cylinder Head LH 3.3L Duratec-V6 . REFER to: Cylinder Head RH 3.3L Duratec-V6 . TEST the system for normal operation after the repair.
Cracked or distorted cylinder head INSTALL a new cylinder head assembly. REFER to: Cylinder Head 2.3L EcoBoost . or REFER to: Cylinder Head LH 3.0L EcoBoost . REFER to: Cylinder Head RH 3.0L EcoBoost . or REFER to: Cylinder Head LH 3.3L Duratec-V6 . REFER to: Cylinder Head RH 3.3L Duratec-V6 . TEST the system for normal operation after the repair.
Damaged, worn or sticking piston ring(s) INSTALL a new piston ring(s). TEST the system for normal operation after the repair.
Worn or damaged piston INSTALL a new piston and piston pin. TEST the system for normal operation after the repair.
Engine emits excessive black smoke (black/blue/white) Clogged Air Cleaner (ACL) element INSTALL a new ACL element. TEST the system for normal operation after the repair.
Incorrect type or grade of oil DRAIN and FILL with specified oil.
Blocked or restricted turbocharger oil drain pipe INSPECT the turbocharger oil drain pipe. REPAIR as necessary. TEST the system for normal operation after the repair.
Damaged/restricted or leaking turbocharger intake tube assembly REPAIR or INSTALL a new tube as necessary. TEST the system for normal operation after the repair.
Engine wear (piston rings, valve guides) REPAIR as necessary. TEST the system for normal operation after the repair.
Plugged crankcase ventilation system Visually INSPECT the crankcase ventilation system.
Turbocharger oil seals leaking REFER to Turbocharger Internal Oil Leak Test. REFER to: Turbocharger 2.3L EcoBoost . or REFER to: Turbocharger 3.0L EcoBoost . TEST the system for normal operation after the repair.
Low or no oil pressure after an oil change 2.7L GTDI only Oil filter housing REMOVE the oil filter housing. INSPECT the oil filter housing for a missing or damaged center stem. INSPECT for a missing or damaged O-ring seal on the stem. REPAIR as necessary. TEST the system for normal operation after the repair.