The car would drive normally while accelerating. But, during deceleration all the way to a complete stop, the idel would hover around 1200 to 1500 RPMs and pulsate for about 20 secs. After that, it would gradually come down to 900 RPM's. Once it gets there, it would be stable and normal. Does anybody know what can be wrong. On colder days (30F and below), it does this on higher RPM's (around 2K) and pulsates longer.

Of course, this would be more noticeable when sitting at a light after normal driving. I thought it would go away after the car warms up. But, it does not.

Thoughts anyone. Much appreciated.