strange idle issue

[joeWM]

its been getting colder out, and lately ive noticed that when i start it up in the mourning which is usually about 6am, it idles at about1500-2000 when cold, i usually let it warm up for about a min or so, but when im driving down the road, and go to shift, i let off ,push in the clutch and the rpms go up about 1k, thats just when i push in the clutch, does it thro all gears, then when im down at the highway, about a mile from the house, it doesnt do it at all.
anyone have any thoughts?

[codfizzle]

Perhaps your IAC is gummed up. This happened to me once. Every time i would stop at a light and put it in neutral, the RPMs would go up to about 1500. I think the IAC is gummed up, and in cold temps, that gummy buildup is more stiff and thick and would prevent the IAC from adjusting as fast as it's supposed to.

There are ways to clean the AIC, although I've never tried them because my problem just kinda went away on its own after a few days. But be very careful about what to use to clean it if you go that route. I've heard of people using carb cleaner to clean it, and it actually made the AIC seize up altogether. That's a $350 problem, just from using the wrong fluid to clean it. I'm not sure what would be the best for that job.

I would just give your car a few minutes more warm-up time to let some of that engine heat warm up the IAC and loosen up that sticky greasiness a bit.

[Buffman]

I use throttle body cleaner on mine. Still spun nice and free when I was done with it.

[adema2626]

Also check the tension on your throttle cable because if that is just a little to tight it does that. But it is most likely the IAC which i have that issue with mine.