Why is my idle so high when I stop in traffic?

Sometimes cleaning all that stuff can remove years of accumulated junk in small pasageways, especially around the butterfly vavle in the throttle body. This in turn allows more air into the motor than it's used to. Much like having the throttle part way open. Most newer vehicles have a learning mode. You can try unplugging your battery and letting it sit for an hour and then connect it back. This should clear the ECU memory, and the vehicle will have to go throught the learn function again. When you start the car and let it idle, DO NOT run the A/C or lights, or defroster, or anything that may put extra drain on the motor. The computer needs to establish a baseline for idle, so let it just sit and idle for a few minutes. See if that helps with the idle issue.
My wife's 06 Pathfinder started acting up after I wiped out the junk in the throttle body. It kept giving an error causing the check-engine light to come on. I would clear it and it would come back on in a day or two. After a week or so, it finally stopped coming in.