You will have to drive around for a while for the ECM to relearn the engine. Engine will run rough while relearning which might cause a false knock detection.
Try resetting the ECM again. Pull battery cable and step on brake pedal for a few seconds. Reconnect battery. For a MY 2009, you will need to reset the windows (several threads about that on this site) and you will lose your radio presets.
Clean your MAFs. Very easy job and only takes 5-10 minutes. Dirty MAFs can cause weird problems.
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