Punto GT engine knocking.

Hi all.

Does anyone know why the engine is doing the following,
And what would be needed/involved in fixing?

The engine is lacking power, it runs ok if you don't exceed 5500-6000rpm
If you put your foot down it knocks.

I know this is very vague, but does anyone have any ideas what it could be?
Could it be cam wear?

Cheers

Have you tried doing a blink test to check for any errors stored on the ecu?

No, I haven't done that yet, as it sounds as though it's mechanical.
For what it's worth, I'll try the "blink test" but I have a feeling it's something to do with the camshaft.

Get a video up so we can hear the knocking.