right directly on the bottom of the throttle body, i think there are for screws holding it on, take the throttle body off, mark your vac. hoses so they dont get mixed up, remove the for screws on the bottom of the throttle body and clean that bad boy out with carb cleaner!! what it is is a little valve that either uses the coolant or air to control the amount of air bypassing the butterfly (Throttle) and when the air/coolant warms up it opens or closes the valve!! so when you put on the brakes it has a sensor that tells the computer to shut the fuel off for a second and then it revs back up again!! that problem pissed me off so bad i looked everywhere trying to figure it out and found a master toyota mechanic that solved it for me!!! check it out and it will solve that annoying problem, hopefully that does it for ya!
