Lack of Power, Sluggishness, or Sponginess

Lack of Power, Sluggish or Spongy

Checks	Action
DEFINITION: The engine delivers less than expected power. Little or no increase in speed when the accelerator pedal is pushed down part way.
Preliminary Inspections	Refer to Important Preliminary Inspections Before Starting in Symptoms - Engine Controls . Search for bulletins. Verify that the engine control module (ECM) grounds are clean, tight, and in the correct locations. Remove the air filter element and inspect for restrictions. Refer to Air Cleaner Element Replacement and replace if necessary.
Fuel System	Test for incorrect fuel pressure. Refer to Fuel System Diagnosis . Test for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (W/O Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (W/Special Tool) . Test the fuel injectors. Refer to Fuel Injector Coil Test . Test or inspect items that can cause an engine to run rich. For a rich condition, refer to DTC P0172 . Test or inspect items that can cause an engine to run lean. For a lean condition, refer to DTC P0171 .
Sensor/System	Test for the correct operation of the intake manifold tuning valve (IMTV) system. Refer to Intake Manifold Tuning (IMT) Valve Diagnosis . Use a scan tool in order to monitor the knock sensor (KS) system for excessive spark retard activity. Refer to Knock Sensor (KS) System Description and DTC P0327 .
Ignition System	Wet down the secondary ignition system with water from a spray bottle. Wetting the secondary ignition system may help locate damaged or deteriorated components. Look/listen for arcing or misfiring as water is applied. Test the ignition voltage output with the J 26792 Spark Tester. Refer to Electronic Ignition (EI) System Diagnosis . Remove the spark plugs and inspect for the following conditions: Incorrect heat range Wet plugs Cracks Excessive wear Improper gap Burned electrodes Heavy deposits Refer to the following procedures: SPARK PLUG INSPECTION Spark Plug Replacement Ignition System Specifications An incorrect spark plug gap will cause a driveability concern. Refer to Ignition System Specifications . If the spark plugs are fouled by gas, coolant, or oil, determine the cause before replacing the plugs. Refer to the following procedures: For diagnosis of a rich condition, refer to DTC P0172 . For diagnosis of coolant or oil fouled spark plugs, refer to Loss of Coolant in Engine Cooling or Symptoms - Engine Mechanical in Engine Mechanical - 1.6L (L91). Test the crankshaft position (CKP) sensor for the correct resistance. The CKP sensor resistance may be out of range after a hot soak. The resistance should be between 460-620 ohms. Inspect the ignition coil for cracks or carbon tracking.
Engine Mechanical	Inspect for excessive oil in the combustion chamber and for leaking valve seals. Test for low cylinder compression. Refer to Engine Compression Test in Engine Mechanical - 1.6L (L91). Inspect the combustion chambers for excessive carbon buildup. Clean the chambers with top engine cleaner. Follow the instructions on the can. Inspect the following for incorrect basic engine parts: The camshaft The cylinder heads The pistons, connecting rods, and bearings Refer to the following procedures in Engine Mechanical - 1.6L (L91): Cylinder Head Replacement Camshaft Replacement Piston, Connecting Rod, and Bearings Cleaning and Inspection
Additional Inspections	Inspect the following exhaust system components: The exhaust system for physical damage. The mufflers for heat distress or possible internal failure. The three-way catalytic converter(s) for restrictions. For more information, refer to Symptoms - Engine Exhaust in Engine Exhaust. Test the transmission torque converter clutch (TCC). Refer to Symptoms - Automatic Transmission in Automatic Transmission - Aisin (81-40LE).