For 1990-2009 cars

#### Lack of Power, Sluggish or Spongy

Checks | Action
--- | ---
Definition: Engine delivers less than expected power. Little or no increase in speed when the accelerator pedal is pushed down part way.
Preliminary Checks |

• | Powertrain On Board Diagnostic (OBD) System Check

• | Intermittent Conditions .

• | Search for bulletins.

Fuel System Checks |

• | Check the system fuel pressure. Refer to Fuel System Pressure Test .

• | Check the fuel injectors. Refer to Fuel Injector Balance Test , Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Between 10-35 Degrees C (50-95 Degrees F) or Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Outside 10-35 Degrees C (50-95 Degrees F) .

• | Check for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

• | Check items which can cause an engine to run rich (long term fuel trim is significantly in the negative range). Refer to DTC P0172 Fuel Trim System Rich .

• | Check items that can cause an engine to run lean (long term fuel trim is significantly in the positive range). Refer to DTC P0171 Fuel Trim System Lean .

Sensor/System |

• | Using a scan tool, monitor KS system for excessive spark retard activity. Refer to Knock Sensor (KS) System Description .

• | Check the EGR system for proper operation. Refer to Exhaust Gas Recirculation (EGR) System Description .

• | Check for a restricted air intake system. Refer to Air Intake System Description .

Ignition System |

• | Check for proper ignition voltage output using the following steps:

- | Clip the spark tester J 26792 to engine ground.

- | Connect one end of a spark plug wire to the spark tester; leave the other end of the spark plug wire to the coil being tested.

- | Connect one end of another spark plug wire to the other coil tower; connect the other end of the spark plug wire to ground.

- | Crank the engine while observing the spark tester; a crisp blue spark should be observed.

- | Repeat the above steps for each coil.

• | If adequate spark is not present at the coil(s), check for the following conditions:

- | Coil(s) - Cracks, carbon tracking/arcing, or a resistance value outside the specified range.

Coil Resistance
5000 - 7000ohms (5K - 7Kohms)

- | Spark Plug wires - Signs of arcing/cross firing, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range.

Spark Plug Resistance
7000ohms (7Kohms)

| Important: : Spraying the secondary ignition wires with a light mist of water may help locate an intermittent problem. Ignition components will arc to ground when a secondary component is faulty.

- | Defective module.

- | Ignition System Wiring - Loose ignition module feed or ground connection, or damaged system wiring.

• | Remove spark plugs and check for the following:

- | Fouled plugs

- | Cracks

- | Wear

- | Improper gap

- | Burned or damaged electrodes

- | Improper heat range or reach

• | If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.

Engine Mechanical |

• | Excessive oil in combustion chamber-Leaking valve seals.

• | Low cylinder compression.

• | For incorrect basic engine parts. Inspect the following:

• | Camshaft

• | Cylinder heads

• | Pistons, etc.

Additional Checks | Check exhaust system for possible restrictions. Check for the following:

• | Inspect exhaust system for damaged or collapsed pipes.

• | Inspect mufflers for heat distress or possible internal failure.

• | For possible plugged Three-Way catalytic converter. Refer to Restricted Exhaust System Check and Exhaust System.

• | Check for proper TCC operation. Refer to Torque Converter Clutch Evaluation and Diagnosis in Automatic Transaxle -- 4T60-E.