Hey fellas for whatever reason every time im at a light or idle my car dropping below 1 rpms and starts rattling and sometimes even cuts off unless i give it some gas, now i know i need to change my oxygen sensor but im sure that cant be the reason, maybe i need a new intake? also im sure the car is well over due for a tune up not sure if they will help at all but any reasons it could be doin that?

 

I think that you answered your own question. (tune up)
check for vacuum leaks.

 

check for codes before you start spending money.