Detonation/Spark-Knock/Pings

SYMPTOM:
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 COMPUTERS AND CONTROL SYSTEMS


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


Incorrect fuel pressure Proceed to FUEL PUMP


Vacuum leak Inspect vacuum hoses for
proper routing and damaged lines
Check intake manifold and
throttle chamber base