hey fellow X-ers,

Hey, in the past few weeks, on a cold start-up, my engine seems to be rattlin. After my engine warms up, it disappears(5-10 minutes of drivin). I did my best open the hood and check for any lose bolts, but haven't done any mods other than K&N intake. Hope you all can help me out, or might have to take it to the nissan shop and get crazyily charged. Oh by the way, my 5spd X only has 33K miles and reguarly keep up with scheduled maintanence. Thanks in advance.