i have a 99 GT 5spd. on occation when i start the car it will run for a couple seconds then stumble until the point where it almost stalls, if i give it a little gas it will idle fine. then when driving if i pull up to a stop it does it again, almost stalls, then tries to idle under 500 rpm then will eventually catch itself. the thing is, it doesnt do it every time, sometimes will be just fine, but every once in a while will screw up. i though maybe it was a vacuum leak, so i looked all over for a loose line or crack in the manifold, couldnt find anything, had a friend listen to it, he says it sounds like it could be a vacuum leak, but he couldnt find it either. sooooooo does it sound like a possible vacuum leak? if so how the hell can i track it down?