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 |
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 | INSTALL a new valve in the cylinder head. 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. TEST the system for normal operation after the repair. | |
| Inoperative or damaged cooling system | REFER to Engine Cooling . | |
| Fail-safe cooling invoked (if equipped) | REFER to the Engine Controls - Symptom Charts (Except Diesel & Hybrid) . | |
| Poor idling | Vacuum leaks | Refer to the appropriate Engine article for the procedure. REFER to the Engine Controls - Symptom Charts (Except Diesel & Hybrid) . |
| 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 the Engine Controls - Symptom Charts (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. TEST the system for normal operation after the repair. | |
| Damaged head gasket | 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 |
Refer to the appropriate Engine article for the procedure. |
| Fail-safe cooling invoked (if equipped) | REFER to the Engine Controls - Symptom Charts (Except Diesel & Hybrid) . | |
| Burnt or sticking valve | INSTALL a new valve in the cylinder head. 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 pipes | INSPECT the turbocharger oil drain pipes. 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 turbocharger housing or exhaust manifolds | INSPECT for leaks. Leaks can usually be detected audibly 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 in Fuel Charging and Controls Turbocharger, 3.5L GTDI or Fuel Charging and Controls Turbocharger, 2.0L GTDI . | |
| 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. | |
| 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. 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 | 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. |
| 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 |
Refer to the appropriate Engine article for the procedure. 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 in Fuel Charging and Controls Turbocharger, 3.5L GTDI or Fuel Charging and Controls Turbocharger, 2.0L GTDI . | |
| Damaged exhaust or exhaust leaks at turbocharger housing or exhaust manifolds | INSECT for leaks. Leaks can usually be detected audibly or visually, by a discoloration caused by escaped hot exhaust gases. REPAIR as necessary. TEST the system for normal operation after the repair. | |
| Malfunctioning turbocharger bypass valve | REFER to the Engine Controls - Symptom Charts (Except Diesel & Hybrid) . | |
| Oil level too high | DRAIN oil to correct level. TEST the system for normal operation after the repair. | |
| 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 the appropriate Engine article for the procedure. | |
| Fail-safe cooling invoked (if equipped) | REFER to the Engine Controls - Symptom Charts (Except Diesel & Hybrid) . | |
| Damaged or plugged exhaust system | INSPECT 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 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. 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. TEST the system for normal operation after the repair. | |
| Cracked or distorted cylinder head | INSTALL a new cylinder head assembly. 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 smoke (black/blue/white) | Clogged Air Cleaner (ACL) element | INSTALL a new ACL element. REFER to Intake Air Distribution and Filtering . 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 pipes | INSPECT the turbocharger oil drain pipes. 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 in Fuel Charging and Controls Turbocharger, 3.5L GTDI or Fuel Charging and Controls Turbocharger, 2.0L GTDI . | |