Very Slow Rpm Descend??? Help!!

Hey guys, it seems me and a couple other guys are having the same problems. We have a very slow RPM descend, a very funky idle. Mine goes like this, if I rev it to say 3500 rpm, and release the accellerator, it holds there for a few second, then very slowly begins the descend, stopping and holding around 2500 for a few seconds, then slowly droping to around 1400 rpms for a few seconds, then finally dropping to around 800 rpm idle speed. Probobly takes about 8 seconds to finally come down after rev. Some say it is the IAC which I know gets alot of play in here, but someone else with the same problem has a new IAC and still has the same problem, so what else could it be??? Any help and suggestions are highly appreciated.
Note: Mines been sitting awhile, just now getting aroundto fixing her again. Never had that problem before.

don't know if this is your problem but mines had a check engine light and that same problem and mine was the tempature coolant sensor and it fixed it.

When i set my TPS my car did the same thing.I unhooked the battery for about 10 minutes then it was fine.

rsliger, my coolent light has been on too since I bought it a year ago but levels are fine, but this problem is new. Where is this sensor located??? I'll try to clean it or ebay one for cheap and see how that works out. Hopefully....
i've got to sell this thing. already got a pearl 94, dont need 2 and insurance......OI!!!! damn NY state....

The coolant sensor is located in the overflow tank.Clean the contacts that sit in the coolant with fine sandpaper.

Thanks stroked, god knows I would of spent an hour searching aroudnt he radiator and following every hose off it and looking in all the wrong places. I'll be at the car tomarow to try it out, but guys, still give me other possabilities though, I'd like to have a few likely ideas to trace down when I get to the vehicle tomarow. thanks guys.

After more reading into the IAC, and gathering what I believe to be the workings of it, I dont think this to be an IAC issue. I will still check it out today after I get off work and get over to the shop where it's at, but I dont think the IAC would neccassarily have anything to do with holding RPM so high and acting like that. I think the IAC would cause me low idle problems, but not what i'm describing above. I'll definately try the coolent sensor, cant find alot of reading yet on that, but that also seems a bit reached though too. Any and all suggestions are helpful gentlemen.
Thanks guys. I'll check these post again after work before I get to the car for further suggestions.

Cleaned the coolant contacts onthe sensor, definately needed it, light went out, but still got rpm problem. Unplugged the IAC, didnt die, didnt "honk", but it did seem to run a little smoother. cleaned contacts and maf contacts, did notice though that it didnt have rev problem until engine warmed up after a minute or so. Tried butane around the hoses, etc. Still trying to figure out hte problem. It has sat for an extensive period of time (at least a year on my part, maybe more on previous owner) hasnt actually seen miles in a long time, does it sound like she needs to relearn???? batteries been unplugged a while, numerous times. Any ideas. Though after doing all the above, the rev problem did seem to get a little better, it doesnt stay stuck so high for so long, takes about 5 seconds roughly to get back down rather than 10 like before.

it's not the sensor in the coolant tank I was mentioning it in the sensor right across from the oil filler tube it tells the computer that the car cold and adds more fuel for starting.

hmm, it's storming out right now so I cant check itout, but can you be more descriptive on that so I'm not pulling the wrong sensors. Across from oil filler tube?? meaning towards the engine, passenger side, drivers, etc. and rough dimensions if you could. that way I know what i'm looking for when I pop the hood again. It still does the RPM issue, but not quite as bad, but now that hte ABS has finally been done and tranny done, now that it's finally onthe road i'm noticing that other issues too. When I give it gas, the psi shoots way high, but it takes a couple seconds before the gas and rev kick up. Also noticed the damn speedo doesnt go above 45. issues...issues....issues. welp, one thing at a time now, now watching ebay for another gauge cluster.

it's the sensor on the passenger side and it's by the font of the valve cover that goes into a water line. hope that helps if not let me know.