Withdrawal
Allow the engine to cool completely, then release pressure from the fuel injection system.
Disconnect the ground wire from the battery.
Drain some coolant to bring the level below the intake manifold. If the coolant is not contaminated or discolored, it can be reused.
Loosen the clamp and disconnect the large intake duct from the throttle body. It may be necessary to remove the complete air filter/intake duct assembly to create sufficient working space.
Disconnect the coolant hoses from the throttle body/intake manifold.
Disconnect the accelerator pedal cable and, if equipped, the cruise control cable.
Remove tube and EGR valve (EGR).
Disconnect the vacuum hose from the fuel pressure regulator and disconnect the electrical connectors from the fuel injectors.
Disconnect the fuel lines from the fuel line.
Disconnect any remaining hoses and wires attached between the intake manifold/throttle body assembly and the engine or body.
Remove the bolts and/or nuts securing the manifold to the cylinder head. Start at the ends and move towards the middle of the manifold, loosening each fastener a little at a time. Support the collector so that it does not fall.
Note: The manifold can be removed without removing the throttle body, injectors, throttles, fuel pressure regulator and carburetor. If the manifold is to be replaced, replace all external components and pipes on the new manifold before installing it on the cylinder head.
Move the manifold up and down to release the gasket, then lift it off the head and remove the gasket.
Installation
Remove the old gasket, then carefully clean all traces of sealant from the contact surfaces of the manifold and head. Be very careful not to scratch the soft aluminum surfaces. On sale there are special solvent compositions that will greatly facilitate the task. Make sure surfaces are clean.
Check the manifold for deformation, cracks, signs of corrosion or other damage. Cracks and warping of the surface are usually found near the gasket. If damage is found, have a specialist repair or replace the manifold.
Always use a new gasket when installing the manifold. If one side of the gasket is coated with graphite, it must face the cylinder head
Install the nuts and bolts and, moving from the center to the ends, gradually tighten them to the required torque.
Then install in the reverse order of removal.