Section 1558 (Engine Controls And Fuel - 3.5L (L66) - Troubleshooting & Diagnosis): Backfire

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

Backfire

Checks	Action
DEFINITION: The fuel ignites in the intake manifold, or in the exhaust system, making a loud popping noise.
Preliminary Check	Refer to Diagnostic System Check - Vehicle . Refer to Symptoms - Engine Controls .
Ignition System Checks	Check for the proper ignition coil output voltage with a J 26792 Spark Tester or equivalent. Inspect the spark plugs for correct operation and good ignition system performance. Refer to Spark Plug Inspection . Inspect the ignition coil boots for damage.
Engine Mechanical Checks	Check for any of the following engine mechanical problems: Any broken or weak valve springs A low compression Any sticking or leaking valves An incorrect valve timing An incorrect or worn camshaft Refer to Symptoms - Engine Mechanical . Check the intake and the exhaust system for casting flash or other restrictions.