By referring to the service manual
Check the current according to the table that I provide in the attachment.
Make sure that your battery is 75D23L not 55D23L or 65D23L. In Saudi Arabia, we got it from the dealer fitted with 55D23L which have a weak current either for starting or hard driving.
Weak current leads to lake of power to the ignition coils which in result leads to poor ignition spark. Poor ignition spark will leads to insufficient explosion of the A/F that will leads to knock and then problems with the engine.
During this time, the ECU will try to correct that by reducing the amount of fuel and a retraction of the engine performance.<== I'm not sure about this one but this is what I feel if I'm driving a BLE with a not good battery or alternator and this happened also if the weather reached more than 40 degree celsius.
And by the way, my name is Majed
