Removal, Overhaul & Installation

Disconnect battery and drain cooling system. Relieve fuel system pressure, see FUEL SYSTEM in BASIC TESTING article. Disconnect and label all wire connectors, vacuum hoses, fuel lines and cable linkages from throttle body.
Unbolt and remove throttle body assembly from manifold. See INJECTOR (TBI) in this article for injector removal procedure. Disassemble throttle body except for fuel pressure regulator and air valve (these units are not serviceable). See Fig 1 . Blow out all passages with carburetor cleaner and compressed air. DO NOT immerse throttle body in water or cleaning solution, as component damage will result.
To reassemble, reverse removal procedure. Tighten TBI body halves assembly screws to 31 INCH lbs. (3.5 N.m). Use new base gasket with no sealers. Tighten throttle body-to-manifold bolts to 17 ft. lbs. (23 N.m). Refill cooling system. Reconnect battery.

Fig 1: Exploded View of Throttle Body

Courtesy of GENERAL MOTORS CORP.