You guys are probably having problems with your start air idle control valve. It's the small one on the very right of the intake mani. There is a rubber plunger inside that is spring actuated. My car would rev up and down and almost stall out when i took my foot off the gas. I opened up the valve and the rubber piece had lodged itself sideways. took it off and made a block off plate. When it's cold it will drop revs and almost stall (by cold I mean outside temp and it hasn't been started, like overnight). Once it heats up for five seconds it works fine. The reason it continually does this is because the airway is stuck open.
To test if this is the problem, take your intake tube off. There are two holes in the throttle body before the butterfly. Have someone start the car and hold your finger over the hole at the bottom. It shouldn't do it if that's the problem, if I remember correctly, I fixed this about two years ago on my car.
The plunger moves after the engine is at temp and closes this airway.
