If you are planning to remove it anyways, you can take them off before taking out the manifold, but otherwise, you may just leave throttle body and plenum assembly on. First unplug the negative battery terminal and then release fuel injection system. When necessary, drain the cooling system and remove either the air cleaner (for carbureted models), air intake case (for throttle body fuel-injected models), or disconnect air intake pipe (for multi-port fuel-injected models). Label them before detaching any of the hoses, wires, brackets, and emission lines connecting them to the carburetor/throttle body and intake manifold. Close off fuel lines and cap fittings to prevent leakage. For carbureted models this means disconnecting at the carburetor; for throttle body fuel-injected models this means disconnecting at the throttle body assembly; for multi-port fuel injected models consider raising vehicle and supporting on jackstands for easier access. Use a backup wrench while detaching an MFI fuel feed line. However, detach also from carburetor/throttle body any throttle cables and cable going from carburetor/throttle body to transmission (for automatics only) along with cruise control cable if applicable. On multi-port fuel-injected models remove three brackets that secure intake manifold/intake plenum assembly to engine block. Unscrew bolts/nuts holding intake manifold to engine using socket, ratchet and extension. If it sticks a little bit gentle hit it with soft-face hammer without prying against or tapping on carburetor/throttle body. Note clamp locations below bolts/nuts if there are any. After removal make sure that both surfaces have been cleared of all old gasketing material including aluminum areas which should not be scratched or gouged during cleaning process. Gasket removal solvents may be used if necessary. Install new gasket onto manifold tighten bolts/nuts progressively torquing from center outwards. Finally, reassemble other parts in reverse order, add coolant, start the engine and test it for leakage as well as proper operation.