hey all - long time reader first time poster.

Thought Id test some brains here before posting locally.
I have a 2002 JDM EP3R , k20a engine. Stock. Around 40,000miles. Clutch needs replacement otherwise runs fine. I have owned the car for a few months and have replaced most parts bar the transmission fluid with OE fluids/parts.
Spark plugs are new iridium items to suit.

I have noticed recently - that at several occasions or perhaps randomly , that the motor has been pinging/preigniting under light load and very slight hills.
1st/second gear , at low to medium RPMs it will very lightly rattle alittle and this will disappear quickly as you accelerate.
The engine feels strong and makes no noticeable noise at any other rpms or under any other situation.
I understand most if not all hondas are designed to do this alittle depending on fuel RON and load etc.

Its disconcerting to say the least and ironically makes me drive slower , throttle slower/softer and thus the same situation keeps happening.

What avenues should I look at replacing/checking out on the engine and its running ?
VTC issue ? timing chain/tensioner issue ? or even very worn clutch chattering or ?