Detonation Spark Knock

DEFINITION: A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with throttle opening.

POSSIBLE CAUSE ACTION

Lean operating condition ^ Check computer controls.
Refer to COMPUTERIZED ENGINE CONTROLS.

Poor or contaminated fuel ^ Check for excessive alcohol content.
Recommend higher grade fuel.

Incorrect fuel pressure ^ Check fuel pressure

Vacuum leak ^ Inspect vacuum hoses for
proper routing and damaged lines.
^ Check intake manifold and throttle body.