Rattle when idle
 

I have a slight rattle almost not able to be heard when I'm idling but when I engage the clutch the rattling stops ...any suggestions ? You can barley hear it but of course I'm always looking for weird noises or wired etc

is it like bird chirping sound? Might be clutch slave cylinder going bad.

No thankfully no chirping just a slight rattle like equivalent to not tightening a bolt and hearing the loose bolt rattle a bit ..its barley audible

Could be a lot of things...heat shields rattling are pretty common. When they get hot, they expand and with the just the right idle speed a resonance is set up and a rattle is heard. Change speed and it goes away.
Since it also goes away with the clutch depressed you could check the clutch linkage/rods to make sure they're snug (but not too snug).

Most likely the dampening springs on the clutch disc if the noise goes when you press the clutch. You running an aftermarket clutch? Mileage on it? As the springs wear with time they develop more play and can cause the noise you described. Of course could be some other things but since the noise goes when you press the clutch pedal I'd put my money on the clutch disc springs or something associated with the clutch assy.

Thanks man .. That would suck I just got an ACT Heavy duty ..im gonna get it checked out

Just for Curiosity's sake..reach in a grab the shifter fork on the trans top of trans inside engine bay,near firewall)..see if you can wiggle it..If you can there is your problem.
Also thinking of Catalytic shields.

Some NEW Throw out will have that "rumble" when you have the clutch in.
I found that out when I changed a clutch on one of the many cars I went through.
The Good news is that you can get a TOB for a First gen that will be make better than the one for a 2nd Gen.

get it checked but I wouldn't worry too much about it, my act clutch has a very faint noise which goes when I press the clutch pedal, forget it's there after a while.

Also it might be the the spring on the clutch fork vibrating slightly and then under pressure it goes. Early rx7 clutch forks suck they updated the design of them in 94/95 can't remember which year.....so when ever getting a clutch, if your running the old 93 fork get a newer one for insurance.