Symptom Chart - Engine Performance

SYMPTOM CHART - ENGINE PERFORMANCE

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 Damaged charging system/battery Burnt valve Worn piston Worn piston rings Worn cylinder Damaged head gasket Inoperative or damaged cooling system Fail-safe cooling invoked (if equipped)	Refer to the appropriate Engine article, for the procedure. REFER to the INTRODUCTION article. REFER to CHARGING SYSTEM . INSTALL a new valve in the cylinder head. TEST the system for normal operation after the repair. INSTALL a new piston. TEST the system for normal operation after the repair. INSTALL new piston rings. TEST the system for normal operation after the repair. INSTALL a new cylinder block. TEST the system for normal operation after the repair. INSTALL a new cylinder head gasket. TEST the system for normal operation after the repair. REFER to ENGINE COOLING . REFER to the INTRODUCTION article.
Poor idling	Vacuum leaks Inoperative or damaged ignition system Inoperative or damaged cooling system Inoperative or damaged fuel system Fail-safe cooling invoked (if equipped) Incorrect valve clearance Incorrect valve-to-valve seat contact Damaged head gasket	Refer to the appropriate Engine article, for the procedure. REFER to the INTRODUCTION article. REFER to ENGINE IGNITION - 3.5L . REFER to the INTRODUCTION article. ADJUST valve clearance. REFER to ENGINE - 3.5L . TEST the system for normal operation after the repair. INSTALL a new cylinder head. TEST the system for normal operation after the repair. INSTALL a new cylinder head gasket. TEST the system for normal operation after the repair.
Engine runs rough	Inoperative or damaged fuel system Air or vacuum leaks Inoperative or damaged cooling system Inoperative or damaged ignition system Fail-safe cooling invoked (if equipped) Burnt or sticking valve Weak or broken valve spring Carbon accumulation in combustion chamber	Refer to the appropriate Engine article, for the procedure. REFER to the INTRODUCTION article. INSTALL a new valve in the cylinder head. TEST the system for normal operation after the repair. INSTALL a new valve spring. TEST the system for normal operation after the repair. ELIMINATE carbon buildup. TEST the system for normal operation after the repair.
Excessive oil consumption	Leaking oil Inoperative PCV system Incorrect oil Worn valve stem seal Worn valve stem or valve guide Sticking piston rings Worn piston ring groove Worn piston or cylinder	REPAIR oil leakage. TEST the system for normal operation after the repair. REPAIR or INSTALL new components as necessary. TEST the system for normal operation after the repair. CHANGE oil to correct specification. INSTALL a new valve stem seal. TEST the system for normal operation after the repair. INSTALL a new cylinder head. TEST the system for normal operation after the repair. INSTALL new piston rings. TEST the system for normal operation after the repair. INSTALL a new piston and piston pin. TEST the system for normal operation after the repair. 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.
Coolant in oil	Leaking head gasket Damaged cylinder block Damaged cylinder head Damaged coolant pump/seal/gasket	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 Oil level too high Incorrect engine oil Excessive accessory drive belt loading Inoperative or damaged cooling system Fail-safe cooling invoked (if equipped) Damaged or plugged exhaust system Incorrect tire size Dragging brakes Slipping transmission Incorrect valve clearance Worn or damaged valve tappet Damaged valve guide Compression leakage at valve seat Seized valve stem Weak or broken valve spring Worn or damaged cam Damaged head gasket Cracked or distorted cylinder head Damaged, worn or sticking piston ring(s) Worn or damaged piston	Refer to the appropriate Engine article, for the procedure. REFER to the INTRODUCTION article. DRAIN oil to correct level. TEST the system for normal operation after the repair. INSTALL correct specification engine oil. TEST the system for normal operation after the repair. Refer to the appropriate Engine article, for the procedure. REFER to the INTRODUCTION article. INSPECT exhaust system. REFER to SUSPENSION SYSTEM - GENERAL INFORMATION . REFER to BRAKE SYSTEM - GENERAL INFORMATION . REFER to AUTOMATIC TRANSMISSION - 6F50/6F55 . ADJUST valve clearance. REFER to ENGINE - 3.5L . TEST the system for normal operation after the repair. INSTALL a new valve tappet. TEST the system for normal operation after the repair. INSTALL a new cylinder head assembly. TEST the system for normal operation after the repair. INSTALL a new valve spring. TEST the system for normal operation after the repair. INSTALL a new camshaft. TEST the system for normal operation after the repair. INSTALL a new head gasket. TEST the system for normal operation after the repair. INSTALL a new cylinder head assembly. TEST the system for normal operation after the repair. INSTALL a new piston ring(s). TEST the system for normal operation after the repair. INSTALL a new piston and piston pin. TEST the system for normal operation after the repair.