Idling problem... pain in my ass

we just bought this 94 dodge stealth about a month ago. The thing doesnt like to stay at idle where it is supossed to. Sometimes it will be fine and sometimes it likes to sit at about 2 grand. I tried setting the idle the way a website that i found in a forum said but it is still weird. I have no idea what to do now. Any help would be greatly appreciated. Thanks

these cars have several ways to adjust the idle, and a few things that control idle as well.

there is an ISC/IAC motor (idle stepper control/idle air control--same thing just different names for it) on the bottom of throttle body that allows air to bypass the throttle body under certain conditions to maintain a good idle (like when the A/C is turned on, or cruise control is on, etc.). this motor wears out over time b/c these cars are 10+ years old. here is a link useful in diagnosing the ISC: www.dsmisc.com.
here is some more useful info on the ISC:
http://i57.photobucket.com/albums/g236/Linebckr49/3000GT/IAC/IACpage1.jpg
http://i57.photobucket.com/albums/g236/Linebckr49/3000GT/IAC/IACpage2.jpg
http://i57.photobucket.com/albums/g236/Linebckr49/3000GT/IAC/IACpage3.jpg
http://i57.photobucket.com/albums/g236/Linebckr49/3000GT/IAC/IACpage4.jpg
http://i57.photobucket.com/albums/g236/Linebckr49/3000GT/IAC/IACpage5.jpg


in addition to the ISC, the FIAV (fast idle air valve) allows air to bypass the throttle body, as well, but only during start-up before the engine is fully warmed. the FIAV is not adjustable, but rather just wax ball in a valve, that when heated, will close the hole that air was passing through. coolant lines run to the bottom of the throttle body where this valve resides. when the engine heats up, the coolant will warm and heat the wax ball, causing it to close the bypass valve. the FIAV only helps idle during start-up: it increases the idle to aid in engine warm up time. its non-adjustable, as already stated, but if you should clean the throttle body, do not do so with brake cleaner or carb cleaner, because if any of it gets in the 2 holes inside the TB, it could damage the wax ball in the FIAV.

also, you can adjust the TPS (throttle position sensor), there is a BISS (basid idle speed screw) adjustment, and there are screws to adjust the dashpot, which controls the butterfly valve operation. in addition, on the back of the upper intake plenum near the firewall, the throttle cable runs through 2 screws and a bracket. these screws can be loosened and the bracket can be moved side to side to adjust the tension in the cable. you want it as tight as possible w/o opening the butterfly valve.

http://www.3si.org/wiki/index.php/Idle_Speed_Adjustment
http://www.3si.org/wiki/index.php/Idle_Problems
http://www.3si.org/wiki/index.php/FIAV
http://www.3si.org/wiki/index.php/TPS_Throttle_Position_Sensor_Adjustment

was it always used, i bought a 92 stealth, it was like that when i got it, after around 2months of using it, it went to around 750rpm at idle. if it high milage then i dont know

We bought the car about a month ago and i think it only sat for about a month to a month and a half before we bought it. It now has about 108,000 miles on it. I cleaned the throttle body with card cleaner once, and it did screw up the wax ball, so i was told that i could just block off the passage, so i did. The screw by the firewall is set to where it was set at the factory and i was told to not adjust that screw. So i put it to factory spec and left it. I dont know if the IAC is shot, but could that really make such a big difference in my idle RPM? I did pull the throttle body apart and gave it a real good cleaning, replaced any gaskets with brand new ones, and also clead the IAC. So i am not sure what is going on. All the garages that i talk to say that they need to run a diagnostic on it, and i dont have the 50 bucks to spend. I will take a look at some of those sites, though, and see if i cant find anything that will help. I will keep you posted. Thanks