High idle when cold temps outside/moving but ok when stopped

I have a 94 sl2 . Overall car is and has been fantastic for me except for this one issue. In the summer time it seems to do ok when its warm outside but now as the temperature starts dropping out it idles high until I come to a complete stop. my mechanic cant seem to be able to figure it out.I would say it goes to about 1800 to almost 2000 rpms until I stop for about 1 to 2 seconds then it drops back down to normal. any ideas would sooo be appreciated..Thanks John

manual or auto trans?
does this go away when the car is warmed up?
ever replaced the ECT?

manual or auto trans?
does this go away when the car is warmed up?
ever replaced the ECT?
Hi There
Its a manual trans.. It doesnt go away when it warms up while its cold outside but when its warm out it does go down when its warmed up. As silly as this sounds it only runs correctly when the temp outside is like above 80 or so. but this time of year as it gets cooler out it will do this(idle high) through the fall and through the winter. After reading some of these posts on here I am going today to get the ECTS from my saturn dealer. 19.99. I hope this can help and I hope I can figure out how to put it on.In the summer the car runs fantastic. is this common and is there anything else I can do? I cant tell you how much I appreciate the help!!

i think i know what the problem is, but heat shouldn't affect it(at least not to the degree you mention). go ahead and change the ECT, get that old crappy one out of there. a new ECT may help some, but that is not the root of the problem.

let me try to explan this, i don't know of any other car that does this, but the people who programed the saturn PCM are geniuses. saturns with manual tranmission have the PCM programmed to detect basicly how well you drive. when ever the car is moving the computer sets the idle RPM a little higher, so that when you shift the RPMs stay up to prevent damage to the drivetrain from a hard shift. the second you stop, idle drops to normal. like i said, the PCM will detect how you drive and shift and adjust the "rolling idle"(as i call it) accordingly. for example, my car(also a manual trans) 'trusts' my driving skills and and sets the rolling idle relatively low, about 200-300 above the base idle. my car did not like how my ex-girlfriend drove when she was first learning how to drive manual, and set the rolling idle anywhere from 2000 - 3000 RPM. once she finally stopped riding the clutch all the time, it whent down some, but was still fairly high. to prove my theory on this, after you replace the ECT, before you start it up, pull the PCM B fuse, wait a few seconds, and put it back. this will erase the computer's short term memory(fuel maps, spark timing, and shift behaviors) the car may start and die the first time you turn it on, but the second it will start right up. it will run a little rough for the first 5 minutes or so, it is just relearning everything. but i bet the rolling RPMs will be lower then before. i used to pull that fuse everytime i drove after my ex.