Just to add a bit of technique to Jon's excellent info-----if you set up the throttle body in a drill press with a cross slide vise and use a very small center drill to make the initial hole, you'll be much less likely to get it off center. I've also had a lot of success with turning the drill chuck with a pun punch in the chuck holes instead of power-driving it when doing tedious work like this.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!