Symptom Chart: Engine Performance

Diagnostics in this service information assume a certain skill level and knowledge of Ford-specific diagnostic practices. Refer to DIAGNOSTIC METHODS for information regarding Ford-specific diagnostic practices.

Condition	Possible Sources	Actions
Difficult starting	Starter motor mechanical or electrical concern	INSPECT the starting system. INSTALL new components as necessary. REFER to STARTING SYSTEM .
	Plugged catalytic converter	REFER to EXHAUST SYSTEM .
	Air or vacuum leak	INSPECT the air intake system. INSTALL new components as necessary. REFER to INTAKE AIR DISTRIBUTION & FILTERING .
	Inoperative or damaged ignition system	REFER to ENGINE IGNITION SYSTEM - 2.0L-GTDI , or ENGINE IGNITION SYSTEM - 3.5L-TI-VCT for specifications and service informatiom.
	Inoperative or damaged fuel system	REFER to FUEL SYSTEM - GENERAL INFORMATION . REFER to FUEL CHARGING AND CONTROLS - 2.0L GTDI , or FUEL CHARGING AND CONTROLS - 3.5L-TI-VCT . Refer to the appropriate engine/performance service information article(s) for the procedures.
	Burnt valve Worn piston Worn piston rings Worn cylinder Damaged head gasket	CARRY out the compression test. REFER to Compression Test . INSTALL new components as necessary.
Poor idling	Air or vacuum leak	INSPECT the air intake system. INSTALL new components as necessary. REFER to INTAKE AIR DISTRIBUTION & FILTERING .
	Inoperative or damaged ignition system	REFER to ENGINE IGNITION SYSTEM - 2.0L-GTDI , or ENGINE IGNITION SYSTEM - 3.5L-TI-VCT for specifications and service informatiom.
	Inoperative or damaged fuel system	INSPECT the fuel system. INSTALL new components as necessary. REFER to FUEL SYSTEM - GENERAL INFORMATION . REFER to FUEL CHARGING AND CONTROLS - 2.0L GTDI , or FUEL CHARGING AND CONTROLS - 3.5L-TI-VCT . Refer to the appropriate engine/performance service information article(s) for the procedures.
	Incorrect valve-to-seat contact	INSPECT the valve(s) and valve seat(s) for damage. INSTALL new components as necessary. REFER to Valve Inspection .
	Worn or damaged engine support bracket(s) Worn or damaged engine support insulator(s) Worn or damaged transmission insulator and retainer	INSPECT the engine support bracket(s) for damage. INSTALL new components as necessary. REFER to Engine Mount below. INSPECT the engine support insulator(s) for damage. INSTALL new components as necessary. REFER to Engine Mount. REFER to the appropriate engine mechanical service information for ENGINE MOUNT - 2.0L , or ENGINE MOUNT - 3.5L . INSPECT the transmission insulator and retainer for damage. INSTALL new components as necessary. REFER to Transmission Support Insulator. For 6F35, REFER to TRANSMISSION SUPPORT INSULATOR and TRANSMISSION SUPPORT INSULATOR -- ANTI-ROLL . For 6F50/6F55, REFER to TRANSMISSION SUPPORT INSULATOR -- 3.5L TI-VCT , TRANSMISSION SUPPORT INSULATOR -- ANTI-ROLL AWD and TRANSMISSION SUPPORT INSULATOR -- ANTI-ROLL FWD .
Abnormal combustion emissions	Air or vacuum leak	INSPECT the air intake system. INSTALL new components as necessary. REFER to INTAKE AIR DISTRIBUTION & FILTERING .
	Inoperative or damaged ignition system	REFER to ENGINE IGNITION SYSTEM - 2.0L-GTDI , or ENGINE IGNITION SYSTEM - 3.5L-TI-VCT for specifications and service informatiom.
	Inoperative or damaged fuel system	INSPECT the fuel system. INSTALL new components as necessary. REFER to FUEL SYSTEM - GENERAL INFORMATION . REFER to FUEL CHARGING AND CONTROLS - 2.0L GTDI , or FUEL CHARGING AND CONTROLS - 3.5L-TI-VCT . Refer to the appropriate engine/performance service information article(s) for the procedures.
	EGR system fault	Refer to the appropriate engine/performance service information article(s) for the procedures.
Abnormal combustion noise	Carbon accumulation in combustion chamber	INSPECT the cylinder using a Bore scope. ELIMINATE carbon buildup.
Abnormal combustion noise	Gasoline octane too low	VERIFY with customer the type of gasoline used. CORRECT as necessary.
Excessive oil consumption	Leaking oil	REPAIR oil leakage. REFER to Engine Oil Leaks .
	Malfunctioning PCV system	INSPECT the PCV system for damage. Refer to the appropriate engine/performance service information article(s) for the procedures.
	Worn valve stem seal	INSPECT the valve(s) and valve stem seal(s) for damage. INSTALL new components as necessary. REFER to Valve Spring, Retainer and Seal.
	Worn valve stem or valve guide	INSPECT the valve(s) and valve stem seal(s) for damage. INSTALL new components as necessary. REFER to Valve Stem to Valve Guide Clearance .
	Sticking piston rings Worn piston ring groove Worn piston or cylinder	INSPECT the piston(s) and cylinder block for damage. INSTALL new components as necessary. REFER to ENGINE - 2.0L GTDI , or ENGINE - 3.5L-TI-VCT .
Insufficient power	Plugged catalytic converter	INSPECT the catalytic converter for damage. INSTALL new components as necessary. REFER to EXHAUST SYSTEM .
	Air intake system blockage	INSPECT the air intake system. INSTALL new components as necessary. REFER to INTAKE AIR DISTRIBUTION & FILTERING .
	Inoperative or damaged ignition system	REFER to ENGINE IGNITION SYSTEM - 2.0L-GTDI , or ENGINE IGNITION SYSTEM - 3.5L-TI-VCT for specifications and service informatiom.
	Inoperative or damaged fuel system	INSPECT the fuel system. INSTALL new components as necessary. REFER to FUEL SYSTEM - GENERAL INFORMATION . REFER to FUEL CHARGING AND CONTROLS - 2.0L GTDI , or FUEL CHARGING AND CONTROLS - 3.5L-TI-VCT . Refer to the appropriate engine/performance service information article(s) for the procedures.
	Excessive accessory drive belt loading	VERIFY whether the concern is due to normal accessory drive loading. If abnormal, INSPECT the accessory drive system for damage. INSTALL new components as necessary. REFER to FRONT END ACCESSORY DRIVE (FEAD) - EXPLODED VIEW .
Oil in coolant or coolant in oil	Leaking head gasket	CARRY out the cylinder leakage detection test. REFER to Cylinder Leakage Detection .
	Leaking oil cooler	INSPECT the engine components for damage. INSTALL new components as necessary. REFER to Oil Cooler in the appropriate engine mechanical service information article.
	Leaking oil filter adapter	INSPECT the oil filter adapter and seal for damage. INSTALL new components as necessary. REFER to Oil Filter Adapter in the appropriate engine mechanical service information article.