Ive been having this problem from time to time but it seems to happen more often now. Sometimes when i start my car it immedietly idles high but then it falls real low almost to 0 rpm then it idles normal.But at times including once today I started it and it then it shutoff.The second start was fine. I dont know what is causin this it seems to happen after it sits for a while but my thought may be fuel or possible another vacuum leak.Any thoughts?