GM Service Manual Online
For 1990-2009 cars only

Ignition System

Symptoms

Ignition System

Find the symptom in the left column and perform the test/inspection procedure in the right column, be sure to review each cell of the table to identify all tests for a symptom.

    â€¢ Hard Start
    â€¢ Surges/Chuggles
    â€¢ Lack of Power, Sluggishness, or Sponginess
    â€¢ Detonation/Spark Knock
    â€¢ Hesitation, Sag, Stumble
    â€¢ Cuts Out, Misses
    â€¢ Poor Fuel Economy
    â€¢ Rough, Unstable, or Incorrect Idle and Stalling
    â€¢ Dieseling, Run-On
    â€¢ Backfire
    â€¢ Inspect for proper Ignition System operation. Refer to Electronic Ignition (EI) System Diagnosis .
    â€¢ Inspect spark plugs and spark plug wires. Refer to Spark Plug Inspection .
    â€¢ Inspect the spark plugs for correct application. Refer to Ignition System Specifications .
    â€¢ Hard Start
    â€¢ Surges/Chuggles
    â€¢ Lack of Power, Sluggishness, or Sponginess
    â€¢ Hesitation, Sag, Stumble
    â€¢ Cuts Out, Misses
    â€¢ Poor Fuel Economy
    â€¢ Rough, Unstable, or Incorrect Idle and Stalling
    â€¢ Backfire

Inspect the crankshaft position (CKP) sensor for the following:

    â€¢ CKP sensor for damage and proper installation--Refer to Crankshaft Position Sensor Replacement .
    â€¢ Inspect the CKP Sensor and corresponding harness for electromagnetic interference (EMI).