Thanks for the replies guys.
Although it seems like a lean scenario, I can acelerate hard away up 160-180 kph no problem, and can make it happen driving in a straight line without cornering also.
Yes I wish had control over ignition timing, thanks vocky your suggestion of fuel pick up makes sense but it can also happen on a full tank and in a straight line.
I seriously think it may be engine wear(vacuum) that cannot be accomodated with the engine management and sensors. When it's cold no problems at all, it only occurs at normal engine temp and the engine temp is always normal. You would swear it's built up carbon or a hot spot in the combustion chamber.
I found out upping octane rating only temporarily makes it go away, then the management adjusts again and back it comes.
I am now thinking of changing the spark plug gap to try and trick ignition timing, by giving a different reading of combustion pressure.