It sounds like I have a similar problem with my idle. After reading the replies here I'll check all those things. I just made the following post on YotaTech. Any other things I should check? BTW, it's a '94 22R-E.

YotaTech post:
"It will idle just fine when I start it up, but after it gets driven a bit and I come to a stop it will jump back and forth from about 1500 to 1800 RPM. It surges every second; up and back down.

I'm thinking mine has to be a vacuum hose problem somewhere. When I step on the brake the idle drops to about 1000 and surges up to 1200 and back down again. There is some sort of vacuum line on the brake booster, right?

Anybody have any suggestions?
Thanks."