Idle speed problems (fast idle)

[WSCRIVENS]

I have a '96 Sable V6 that has begun having idle speed weirdness.
First, it's intermittent, and every time I take it to the shop, it works fine.
Second we are in Florida so extreme cold is not an issue.
What happens is that after I start the car, it will idle at 900-1000 RPM, even after a warm-up period. If I put it in Neutral, the speed goes up to about 1200 RPM, then slows down to about 600 after a few seconds. As soon as I put it back in Drive, it goes up to 900 again.
Most of the time, if I drive a few blocks to get the engine warm, then stop and immediately restart the engine, it will be OK for the rest of that trip, and sometimes, if I only stop for maybe 1/2 hour it will be OK on the return trip too. If it rests for several hours, the fun starts all over again.

Any help would be welcome!

Walt

[DistanceGuy1]

Purchase and replace your IAC (Idle Air Control) valve. It is a pretty easy fix too.

They are not too expensive either....+- $40.00. Also clean the passages to the valve itself. They could be clogged as well.