today i was driving home from work and was stopped completely at a light. all of a sudden my car just dies..i think it might have something to do with this:

lately my car (at complete stop) has been idling wierd. It will idle fine for a while, but then it will sound like its idling super high for a few seconds and then all of a sudden it will stop for a split second, and then go back to normal(once it starts idling again, the car shakes lightly).

Any help is appreciated. I have no idea what is going on here.