Rattling/clicking noise from motor at idle

[RabidRat]

Since nearly day one that I've had my car back in September '08, I've heard this rattling/clicking noise at idle coming from the motor that seems to come and go. It used to be very rare that it happened, and pretty quiet, but now it's become more frequent and louder.

It never happens when the car's been sitting for a couple hours, only if it's been warmed up or hasn't been sitting long. I only hear the sound at idle up to about 2000 rpm, and never at higher rpms than that.

Any thoughts on what this could be? The fact that the sound doesn't come if it's cold is kinda strange.

[JHatta]

what kind of car

[ToneCapone]

I have a prelude, and when the tranny started going on it... thats what happend.
Double check your transmission fluid and make sure the car dosent jerk around when your driving. good luck

[godwin]

Pop the valve cover and check to see if your oil sprayer line's banjo connectors are intact? or not loose?

[buddy]

exhaust heat shield?

[Yay...Twins!]

If you're using the wrong octane it could be your valves tapping