You don't normally get pinking or knocking on the over run and in normal driving conditions. It usually only occurs when the engine is under load. Mind you top gear in an urban street could have the engine lugging and I would nearly always be in 4th under those conditions.

There is a good article in Wikipedia: https://en.wikipedia.org/wiki/Engine_knocking

I suspect you may have some other cause for the knocking noise. Can you try to describe exactly what you hear with a comparison to some other easily identified sound?

Peter

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