Idle RPM DROPS when engine is warm

I have a 92 Mitsubishi 3000GT, non-turbo, 5 speed.
Upon a cold start, the engine idles fine at about 1000 rpm. However, when the engine warms up the idle drops to between 200-500 rpm and hunts for a stable rpm. It feels like it wants to stall and it has a few times. I put in new plugs, not any better. The idle problem just occurs when the engine is warm. The car runs fine under under acceleration and at speed. The problem only appears when the car is standing still and idling.

Any ideas out there?

Thanks
:banghead:

The problem only occurs when you standing still? What about if you are going say 45mph and push the clutch all the way in, does it idle fine or is it still at a low idle. I know when our cars start up cold they sometimes idle higher than when it warms up as it is kind of on "choke" if you will. I couldnt say for sure but my guess would either be your running rich or possibly the clutch isnt fully disengaged and it is sticking a little(?).

Three letters, IAC

As always Stealthee nails it. IAC:

http://www.stealth316.com/2-isc-iac.htm

If cleaning it doesn't work, I think you can find them relatively cheap on ebay. I think Linebckr or someone said they got one for like $50?

The 4g63 (ie first gen na/turbo, 2g turbo DSMs) have the same IAC as us. And yeah you can usually get them for around $50

IAC= Idle Control Valve

Thanks Everyone. To e-Bay I go.