Idle pulsing then back normal,any idea why?

[Aliakeel]

Hi
Just recently when I drive the car after while and stop or on neutral or sometimes when i start the car after driving (hot)revving up and down 1500 to 2500 rpm and roughly after 15 or 20 sec it go back normal ,but not happening all time it does it sometimes any idea why?or what\'s the Problem ?

Cheers

[Aliakeel]

Anyone know where to start inspect to solve the problem?