To start, turn off the fuel pump, unplug the cable from the battery negative terminal and then wait for about fifteen minutes. Then, the air intake duct has to be taken off as well as the filter housing. Remove the upper intake manifold vacuum hoses and electrical connectors and unbolt and remove the vacuum and electrical connectors from the throttle body and the electronic throttle control system. Remove the EGR Pipe from the upper intake manifold which is followed by the removal of the upper Intake manifold support brackets. Relax the upper intake manifold bolts in the reverse order you tightened them and pull off the upper intake manifold including the foam insulator pad. Thoroughly wash and inspect the sealing surfaces of the upper intake manifold to the lower intake manifold, and if the existing gaskets supplied have damage to them then they should be replaced, however in most cases the gaskets that have been removed will not have any damage and can therefore be reused. The upper intake manifold has to be placed back onto the lower intake manifold and secured by tightened bolts in the proper sequence and using the appropriate torque to get them tightened. To get to the lower intake manifold first you must take off the upper intake manifold after that disconnect any of the hoses that may hinder you when removing the lower intake manifold. Disconnect the fuel rail and the injectors from the lower intake manifold, then 1/4 turn each of the lower intake manifold mounting bolts or nuts starting from the reverse sequence of how they were tighten to allow them to be unscrewed. Sometimes some force may be required to tear the gasket and separate the manifold from the cylinder heads, but do not pry between the manifold and the heads because the gasket sealing surfaces are easily damaged. Clean and inspect the sealing surfaces of the lower intake manifold to the cylinder head; gaskets if bad should be replaced, if not they can be reused. Align the second lower intake manifold to the engine with correct fit of gasket and manifold over the cylinder head. The fuel rail and injectors are inserted to the cylinder heads and lower manifold, and the fuel rail retaining bolts must be loosely put for the proper gasket orientation of the remaining lower intake manifold bolts. Torque the bolts gradually to the measured torque level and then reverse the process of removing them, and start the engine to note any signs of fuel leaks, vacuum leak and coolants leak.