Slight vibration during idle??

When starting the car cold and at a stop light, there is a slight pulsating vibration. What could this be from?

-adam

Welcome to the forum. Could you be more descriptive? You could have bad motor mounts, or it could be a crack somewhere in the body, among other things.

Well if I start the car and just sit there, I can feel a pulsating vibration throughout the car. Its not violent or anything but enough to notice. When I drive away its gone, but when stopped at a light it starts again. on off on off on off. just like that.
-adam

do you hear a popping sound comming out out the exaust or at least feel it when you put your hand hear the exaust pipe..? if so a single spark plug not precisly gapped will cause a miss and do that.. but once rpms climb above 1k you wont notice it...