By bad throttle body, do you mean to exclude the tps (throttle position sensor) and say it's some other part of the throttle body? If so, the one big problem I know of would be air leaking through the throttle shaft area (shaft that holds the 'butterfly' you see when looking through the throttle body). The shaft wears too small or the holes hog out, allowing unmetered air into the intake. This usually causes high or rough idle and lean running. If you meant the tps, then there are steps in the fsm to check it out and even recalibrate it if it's not permanently damaged.