Detonation/Spark Knock

If engine exhibits a mild-to-severe ping or knock (usually worse under acceleration) as throttle position changes, check the following items:

• Perform VISUAL/PHYSICAL INSPECTION .
• Road test vehicle and determine severity of complaint.
• Check fuel injector(s).
• Check for engine overheating.
• Check for restricted air or coolant flow through radiator.
• Check water pump drive belt adjustment.
• Check for correct or faulty thermostat and coolant solution.
• Check Engine Coolant Temp (ECT) sensor for a shifted value.
• Check for a lean system cause for condition. Test drive vehicle while using scan tool to monitor fuel trim. If fuel system is lean, long term fuel trim will be more than 20%
• Ensure there is adequate fuel pressure.
• Check for contaminated or poor quality fuel. Replace fuel with 92 octane rated fuel and reevaluate vehicle performance.
• Check for proper Knock Sensor (KS) operation.
• Ensure ignition timing and controls are working properly.
• Ensure spark plug heat range and gap are correct.
• Check for incorrect or damaged basic engine parts such as camshaft, cylinder heads or pistons.
• Check for excessive carbon build-up on engine components.
• Check for excessive oil entering engine combustion chamber.
• Ensure EGR valve is operating correctly.
• Check for proper air induction operation.
• Check if any Technical Service Bulletins (TSBs) apply.