rough idle with k&n filter fitted e36

[compactdrift]

First off all hello everyone, im new as of today to this site so i thought i would start by asking a question about an issue with my car.

I have a 316i compat 97 which I have recenlty fittied a K&N induction kit (57i) the problem is while the car is stationary in runs quite rough with the revs moving up and down almost as if is about to stall but then it settles. it runs fine when moving. just wondering if anyone had anny suggestion as to how i mite be able to fix it.
also it makes a kind of rattling noise when it idles??? - im planning on fitting a new axhaust within the next week and was wondering if that would help with the airflow and maybe sort it out?

thanks
Craig.

[thekid]

check the connections for the MAF and the AFM. Perhaps take it off and re-do the installation. Where is the rattling noise coming from? Under the hood? The rear of the car? Exhaust will not fix the problem.