Detonation/Spark Knock/Pings

DEFINITION: Engine makes sharp metallic knocks that change with throttle position. Sounds like popcorn popping.

Check for obvious problem such as:
Engine overheating due to loose belts or restricted air flow through the radiator.
Restricted coolant flow through radiator or engine.

CHECK:

- Ignition timing.
- Proper spark plug(s) and gap.
- Poor spark plug wire connections.
- EFI system.
- EGR valve operation.
- Fuel quality.
- Excessive oil in combustion chamber.
- PCV valve operation.
- Visual check for intake gasket leaks.
- ESA system, restricted Exhaust System.
- Clean engine combustion chambers with top engine cleaner.