My car runs smooth transmission shifts good,but when i make a quick stop
it rattles for a quick second and rpm needle moves.I have an 08 5at.does any one know why?

there's no service engine lights on..

 

What do you mean by rattle. Rattling interior? If it's an issue with your rpm's try cleaning your throttle bodies.

 

^no I mean engine,when i make a stop at a red light the car slightly shakes it rattles for like a sec, and the rpm needle goes down and then goes back up.

 

I think it might be that the throttle bodies are dirty.
the idle is rough when i stop

 

Yeah clean the throttle bodies that should help.

 

^OK Thanks

 

https://g35driver.com/forums/v36-diy...le-bodies.html

 

Be careful with the throttle body cleaning, I did my own and tried the diy reset procedure and was only successful at turning the check engine light off, my idle throttle never returned to normal on its own, had to take the car into the dealership to have them reset it via consult II.