Idle Problems!!!!

[rjterry32]

ok guys, heres my problem:
in the morning, when i start my car(its cold in west virginia) it starts just fine. drive for an hour w/ the heater on and temp. only gets up 1/4 way, not even at operating range (1/2 of the way). also, when i get my rpms, up above 2000, say like 3500 and press in clutch for car to drop to idle, the rpms go to 2000, hold for about 3 seconds and then slowly falls down to normal idle at about 1100 rpms. its just a surge in the idle. does this sound like maybe the thermostat is the culprit for the heating problems? i have no clue about the idle but one thing i have noticed is that when i turn my heater off, the idle doesn't act up near as bad.
any help would be greatly appreciated!
Ricky
btw 99 gs eclipse 420a 5spd

 

[Locke]

For heat, check in this order: Full cooling system, thermostat, cap.

For the hanging idle, clean the IAC, and check that the TPS is functioning within it's specified range.

 

[Shadow98]

+1 for Locke

 

[rjterry32]

Found the solution to the crazy idle. Come to find out, it was a blown a/c fuse. This doesn't make sense b/c i haven't ran my a/c in like 2 months. Anyhow, replaced fuse, idles just fine.
Still haven't had a chance to replace thermostat. Fluid level is fine.
Thanks,
Ricky