Symptom Definition
WARNING: This page does not describe the selected car, but rather 19 other vehicles, including the 2003 Hummer H2, 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 GMC Sierra, and 2003 GMC Savana Special. However, it is still accessible from the selected car via links, so may be relevant.
A mild to severe ping, usually worse during acceleration. Engine makes sharp metallic knocks which change with degree of acceleration.