1997 Mitsubishi Pajero automatic Stalling

Hi there,
Im having a problem with my truck stalling when i come to stop at lights etc.. it idles erratically if it doesnt stall... it only does it when the car is warm. if i put it into neutral it comes right straight away.
its very annoying because when its idling the truck lurches forwards sometimes!
it gets serviced every 6 months.. runs like a dream apart from this!! any help would be appreciated...