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.