You can always try resetting the ECU -- with your car already warmed up (do this after a drive), just pull the hazard fuse (it's in the engine compartment fusebox, not the one in the cabin...some people pull the ECU fuse also just to be sure), leave it out for a minute, pop it back in, and start up the car. Don't turn any accessories on, and don't touch the accelerator. Your car will start out idling high, and slowly work its way down to a nice, smooth, low idle. Let it sit there for at least 10 minutes or so before turning the car off. This usually fixes any little idle problems that aren't the result of an ignition problem, bad sensor, etc.