Disconnect the negative cable from the battery. Caution: On models equipped with the Delco Loc II audio system, make sure the lockout feature is turned off before performing any procedure that requires disconnecting the battery. Unplug the oxygen sensor lead. Remove the drive belt and the alternator. Raise the front of the vehicle, support it securely on jackstands, and apply the parking brake. Block the rear wheels to prevent the vehicle from rolling off the jackstands. Unbolt the exhaust pipe from the manifold. Lower the vehicle. Remove the eight exhaust manifold-to-cylinder head nuts/bolts, pull the manifold off the engine, and lift it out of the exhaust pipe flange. Remove and discard the gasket. Scrape off all traces of gasket material from the exhaust manifold and cylinder head mating surfaces. Clean all bolt and stud threads before installation. Use a wire brush on the manifold mounting studs, and a tap works well for cleaning the cylinder head bolt holes. If installing a new manifold, transfer the oxygen sensor from the old manifold to the new one. Installation is the reverse of removal. Be sure to use a new gasket and tighten the nuts/bolts. Work in a spiral pattern from the center out.