I have a 99 4Runner with the 3.4 that idles between 500 and 600 RPMs right after startup, sometimes dipping below that and killing. You can also hear a clicking noise a feel a shake/vibration in the engine bay. See the Youtube video below to see/hear what I'm talking about.

http://www.youtube.com/watch?v=EubzCy5peBg

Once I drive around for a bit, the engine smooths out and idles at 600/700, which seems to be about right. Any help in diagnosing the problem is appreciated.

 

Is the A/C on or off? Kinda sounds like the compressor clicking on and off? But it is hard to tell without hearing it in person.

 

Yeah dude....exactly what nayterobertson said. It sounds like your A/C is trying to kick on but can't. Possibly a bad relay?