For 1990-2009 cars

#### Lack of Power, Sluggish or Spongy

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
DEFINITION: Engine delivers less than expected power Little or no increase in speed when accelerator pedal is pushed down part way.
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? |  | Go to Step 2 | Go to the Powertrain On Board Diagnostic (OBD) System Check
2 |

1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found, correct the condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

Go to Step 16

Go to Step 3

3 | Was visual/physical check performed? |  | Go to Step 4 | Go to Visual/Physical Checks
4 |

1. Remove and check air filter element for dirt, or for being restricted.
2. Replace air filter element if necessary. Refer to Air Cleaner Element .

Was a repair required?

Go to Step 16

Go to Step 5

5 |

1. Check for low fuel pressure. Refer to Fuel System Pressure Test .
2. If a problem is found, repair as necessary.

Was a problem found?

Go to Step 16

Go to Step 6

6 |

1. Check for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Test .
2. If a problem is found, repair as necessary.

Was a problem found?

Go to Step 16

Go to Step 7

7 |

1. Using a scan tool, monitor KS system for excessive spark retard activity. Refer to Knock Sensor (KS) System .
2. If a problem is found, repair as necessary.

Was a problem found?

Go to Step 16

Go to Step 8

8 |

1. Check for proper ignition coil output voltage with spark tester J 26792 :

- | Clip the spark tester to engine ground.

- | Connect one end of a spark plug wire to the spark tester; connect 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.

2. If adequate spark is not present at all coils, repair as necessary.

Was a problem found?

Go to Step 16

Go to Step 9

9 |

1. Remove spark plugs, check for wet plugs, cracks, wear, improper gap, burned electrodes, or heavy deposits.

Notice: Determine the cause of the oil or gas fouled spark plugs in order to avoid damage to the new spark plugs.

2. If a problem is found, repair as necessary.

Was a problem found?

Go to Step 16

Go to Step 10

10 |

1. Check ignition coils for cracks or carbon tracking.
2. If a problem is found, repair as necessary.

Was a problem found?

Go to Step 16

Go to Step 11

11 |

1. Check PCM grounds for being clean, tight and in their proper locations. Refer to Engine Controls Schematics .
2. If a problem is found, repair as necessary.

Was a problem found?

Go to Step 16

Go to Step 12

12 |

1. Check exhaust system for possible restriction:

• | Inspect exhaust system for damaged or collapsed pipes.

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

• | Check for a possible plugged Three-Way catalytic converter by checking exhaust system back pressure. Refer to Restricted Exhaust System Check

2. If a problem is found, repair as necessary.

Was a problem found?

Go to Step 16

Go to Step 13

13 |

1. Check Torque Converter Clutch (TCC) for proper operation Refer to 4T60-E Transaxle Diagnosis
2. If a problem is found, repair as necessary.

Was a problem found?

Go to Step 16

Go to Step 14

14 |

1. Engine mechanical problem Check for low compression, incorrect or worn camshaft, loose timing chain etc. Refer to Engine Mechanical.
2. If a problem is found, repair as necessary.

Was a problem found?

Go to Step 16

Go to Step 15

15 |

1. Review all diagnostic procedures within this table.
2. When all procedures have been completed and no malfunctions are found, review/inspect the following:

• | Visual/physical inspection.

• | Scan Tool data.

• | Freeze Frame data/Failure Records Data.

• | All connections within a suspected circuit and/or system.

3. If a problem is found, repair as necessary.

Was a problem found?

Go to Step 16

Refer to Technical Service Bulletins

16 | Operate the vehicle to duplicate conditions present when the original symptom was noted. Is symptom still present? |  | Go to Step 3 | System OK