Pinging engine when cold

Good day
i have a 2005 LS Aveo , 215000 on the clock .
i experience a sharp pinging noise when accelerating when engine is cold, and have to lift off throttle to make it go away , but returns as soon as accelerating again,so have to creep forward gradually , a bother in traffic around Cape Town .
this lasts until engine reaches half way to operating temp .,, then the noise is gone . have had it at Thorp /GM on and off for around 8 months, all kinds of computer resets ,
the longest the noise was away for was 2 weeks , then it comes back , slowly, until about a week before it is back with a vengence.
Have also replaced the concertina air flow pipe already.
anyone have any experience with this ?
regards