Engine knocking occurs repeatedly. Usually, it becomes particularly notable when accelerating. A sharp metallic sound is produced when the throttle opening angle is changed.
Perform the Diagnostic system check - engine controls.
Check if any problem exists in the vehicle.
Inspect whether smoke is present with combustion noise.
Inspect the fuel quality.
Verify the Injector ID Code of each cylinder.
Check the scan tool data list.
Check for related Service Bulletins.
Compare the Engine Coolant Temperature (ECT), Intake Air Temperature (IAT), and Fuel Temperature parameters while the engine is cold. If the difference between the temperature values is 5°C {9°F} or more when the engine is cold, inspect for high resistance in each circuit and for sensor failure.
{When the ignition switch is turned ON, the MAF sensor is heated, and as a result, the IAT shows a higher value than the normal intake air temperature.}
Observe the Fuel Rail Pressure (FRP) Sensor parameter on the scan tool. It is normal if the Fuel Rail Pressure (FRP) Sensor parameter shows 0.9 to 1.0 V when the ignition switch is turned ON without starting the engine after 30 seconds or more have passed since the stop of engine operation. If not, inspect for high resistance in each circuit and for any sensor failure.
With the vehicle in neutral and idling, completely depress the accelerator pedal while observing the Fuel Rail Pressure (FRP) parameter and Desired Fuel Rail Pressure (FRP) parameter. The difference displayed should always be held to 5 MPa {725 psi} or less.
The CKP sensor is securely installed, and the flywheel is not damaged.
If there is excessive smoke, inspect for an injector that is stuck open. Inspect the combustion chamber for fuel intrusion.
Remove and visually inspect the injector.
Perform the Cylinder Balance with a scan tool.
Perform the Injector Forced Drive with a scan tool.
Observe the Fuel Compensation parameter for each cylinder on the scan tool while idling.
Inspect the air cleaner, air intake duct, and intercooler for clogging, holes, or leakage.
Inspect the compression pressure of the engine.
Inspect the basic components of the engine including the camshaft, the cylinder head, and the pistons.
Inspect the combustion chamber for excessive oil intrusion.
Inspect for any other cause that generates a similar sound, such as loose components, brackets, mounts, or a deteriorated clutch damper spring.