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.

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

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

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