2001 Rav4 - Rough/Low RPM Idle Problem

Hey everyone,

I have a 2001 RAV4with an automatic transmission and 2L gas engine (Canadian market). I have been having what I considered a rough idle for a few years (rougher then it was new, started a year after purchase, dealer saw no problem), but it has gotten markedly worse as of late.

Once the RAV has warmed up (after ~2mins of driving), whenever I come to a stop at some lights, etc and idle it gets very rough, with a lot of shaking being felt through the wheel, seats, etc. I plugged in my OBDII monitor and here is what I found (click the picture to enlarge):

The car idles around 800RPM for the first few minutes, as it should when the outside air tempurature is warm enough for it not to have to enter thecold start loop and idle @ 1,500RPM. That is to say, the RAV idles at the correct "normal" idle of ~800RPM for the first few minutes of operation.

However, once the RAV warms up, the idle falls to ~500RPM and the truck is very rough. Has anyone else experienced this, or know how to correct it? It is my understanding that the idle on the 2.0L is controlled electronically via the IAC valve, so I cannot manually increase the idle, which I would not want to do because it would idle far to high when cold.

I am stumped - ideas?

Thanks!