Micra K12 CR14DE< RATTLES ON COLD START< and BECOME FIT ON IDLE, PLease HELP

I have nissan micra k12 with CR14DE engine. its a flying ,machine but there is a little problem that on cold start< the engine rattles till idle RPM, after that it become fine....
 
The timing chain tensioner operates on oil pressure and being at the top of the engine and on the end of the pressure circuit is the last item to be operated.
 
Top