Dangerous Problem !!

[latief]

I noticed that sometimes my car does something really dangerous. while slowing down to a complete stop (at the traffic light for example), and when it is very slow, it sometimes seems to surge/ jolt forward as if it just changed gears. the result is that the car moves forward suddenly even with my foot on the brake . today i nearly rammed into the guy in-front of me becasue of this....

what is this ? vacuum issue? the car seems to be hunting idle a bit, but drives great otherwise....

thanks,