okay so i got my 00' eclipse GS 2 months ago. when im stopped it'll idle at about 500rpm...sometimes 1k. now it'll vibrate some days A LOT and its loud. somedays, it's silent and it'll still idle the same. if i havent drive the car all day and i decide to start it up, the idle will reach to 3000rpm's and jump a little ...is that normal? what should i do?

 

does it settle back down righ after it jumps or does it kinda jump up and down in the rpms?
BTW: normal idle is somewhere around 800 rpms

 

yeah, it'll eventually get back on track but sometimes i feel like it's going to just like...die. haha...