Where is the throttle body on 1998 Chevy Malibu?

On a 1998 Chevy Malibu, the throttle body is located on the intake manifold, at the top of the engine, near the air filter housing. It's a relatively large, cylindrical component with a butterfly valve inside. To be precise, you'll need to look at the top of the engine, tracing the path of the air intake tube from the air filter; the throttle body is where that tube connects to the intake manifold.