Symptom Chart - Engine Performance

WARNING: This page is about a different car, the 2016 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

Condition	Possible Sources	Action
Difficult starting	Inoperative or damaged ignition system Air or vacuum leak Inoperative or damaged fuel system Inoperative or damaged starting system	INSPECT each system for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure. REFER to the Engine Controls - Symptom Charts (Except Diesel & Hybrid) .
Damaged charging system/battery		REFER to Charging System .
Burnt valve		INSPECT the valve(s) and valve seat(s) for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Worn piston		INSPECT the piston(s) for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Worn piston ring(s)		INSPECT the piston ring(s) for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Worn cylinder		INSPECT the cylinder block for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Damaged head gasket		INSPECT the cylinder head gasket(s) for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Inoperative or damaged cooling system (if equipped, fail-safe cooling invoked)		INSPECT the cooling system for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Poor idling	Vacuum leaks Inoperative or damaged EGR system	INSPECT the EGR and vacuum system for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure. REFER to the Engine Controls - Symptom Charts (Except Diesel & Hybrid) .
Inoperative or damaged ignition system		INSPECT the ignition system for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure. REFER to the Engine Controls - Symptom Charts (Except Diesel & Hybrid) .
Inoperative or damaged cooling system (if equipped, fail-safe cooling invoked)		INSPECT the cooling system for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Inoperative or damaged fuel system		INSPECT the fuel system for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure. REFER to the Engine Controls - Symptom Charts (Except Diesel & Hybrid) .
Incorrect valve clearance		ADJUST the valve clearance. Refer to the appropriate Engine article for the procedure. TEST the system for normal operation after the repair.
Incorrect valve-to-seat contact		INSPECT the valve(s) and cylinder head(s) for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Damaged head gasket		INSPECT the cylinder head gasket(s) for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Engine runs rough	Inoperative or damaged fuel system Air or vacuum leaks EGR system fault Inoperative or damaged cooling system (if equipped, fail-safe cooling invoked) Inoperative or damaged ignition system	INSPECT each system for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure. REFER to the Engine Controls - Symptom Charts (Except Diesel & Hybrid) .
Malfunctioning or damaged air intake system		INSPECT the air intake system for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Burnt or sticking valve		INSPECT the valve(s) and valve seat(s) for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Weak or broken valve spring		INSPECT the valve spring(s) for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Carbon accumulation in combustion chamber		ELIMINATE carbon buildup.
Excessive oil consumption	Leaking oil	REPAIR oil leakage.
Blocked or restricted turbocharge 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 hose clamps. INSPECT for damage and REPAIR as necessary. TEST the system for normal operation after the repair.
Damaged exhaust or exhaust leaks at the 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 the Turbocharger Internal Oil Leak Test. REFER to Fuel Charging and Controls - Turbocharger, 3.5L GTDI . TEST the system for normal operation after the repair.
Malfunctioning PCV system		INSPECT the PCV system for damage. Refer to the appropriate Engine article for the procedure. REFER to the Engine Controls - Symptom Charts (Except Diesel & Hybrid) .
Incorrect oil		CHANGE oil to the correct specifications. TEST the system for normal operation after the repair.
Worn valve stem seal		INSPECT the valve(s) and valve stem seal(s) for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Worn valve stem or valve guide		INSPECT the valve(s) and cylinder head(s) for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Sticking piston rings		INSPECT the piston(s) and cylinder block for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Worn piston ring groove		INSPECT the piston(s) for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Worn piston or cylinder		INSPECT the piston(s) and cylinder block for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Insufficient power	Inoperative or damaged ignition system Air intake system blockage Lubrication system blockage Inoperative or damaged fuel system	REFER to the Engine Controls - Symptom Charts (Except Diesel & Hybrid) .
Turbocharger turbine or compressor wheel damage		INSPECT the turbocharger. REFER to the Check for Free Rotation - Off Vehicle. REFER to Fuel Charging and Controls - Turbocharger, 3.5L GTDI . 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 - Symptom Charts (Except Diesel & Hybrid) .
Oil level too high		DRAIN oil to correct level.
Incorrect engine oil		INSTALL correct specification engine oil.
Excessive accessory drive belt loading		INSPECT the accessory drive system for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Inoperative or damaged cooling system (if equipped, fail-safe cooling invoked)		INSPECT the cooling system for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Damaged or plugged exhaust system		INSPECT the exhaust system for flow and damage. INSTALL new components as necessary. REFER to Exhaust System .
Incorrect tire size		REFER to Suspension System General Information .
Dragging brakes		REFER to Brake System General Information .
Slipping transmission		Refer to the appropriate Automatic Transmission article for the procedure.
Incorrect valve clearance		ADJUST the 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. Refer to the appropriate Engine article for the procedure. TEST the system for normal operation after the repair.
Damaged valve guide Compression leakage at valve seat		INSPECT the valve, valve seat and cylinder head for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Seized valve stem		INSPECT the valve for wear or damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Weak or broken valve spring		INSPECT the valve spring. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Worn or damaged camshaft		INSPECT the camshaft for wear or damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Damaged head gasket(s)		INSPECT the cylinder head gasket(s) for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Cracked or distorted cylinder head(s)		INSPECT the cylinder head(s) for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Damaged, worn or sticking piston ring(s)		INSPECT the piston ring(s) for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Worn or damaged piston		INSPECT the piston for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Oil in coolant	Leaking head gasket Leaking oil cooler Damaged cylinder head Damaged cylinder block	INSPECT the engine components for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Coolant in oil	Leaking head gasket Leaking oil cooler Damaged cylinder head Damaged cylinder block	INSPECT the engine components for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
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 the Turbocharger Internal Oil Leak Test. REFER to Fuel Charging and Controls - Turbocharger, 3.5L GTDI . TEST the system for normal operation after the repair.