Knock only at high speeds

[G_TypeR]

Hi guys,

Ive been experiencing knock recently at high speeds in 6th gear at around VTEC point (MIL set to flash). Ive had the same .cal (civictyper factory) for about 2 years now and with no issues, so I'm assuming there is a problem with the engine rather than with the map itself.

My question is, is there anything I can check while datalogging or any good tests to rule things out. Ive recently changed the oil and spark plugs which hasn't improved the problem.