Few questions about shaking, idle and exhaust
 

Whenever I rev my engine after it roars I feel a slight dundundun....shake kinda. Not sure if I can explain it any other way but does anyone know if it's normal? If not, what might it be?

After I revved the exhaust started to have white/grey smoke come out and smelled really bad, like gasoline. I haven't started the car up in about 2 weeks so could that of been why?

and Lastly, after I turn my car on the idle stays in between 1 and 0 so around 500 RPM i think, again is this normal? What is it supposed to be idling at and how can I fix it if it's supposed to be higher? Thanks for any help!

its running rich it sounds to me check the o2's check engine mounts for cracks keep an eye and the conditions of when it smokes and post again