The intake manifold is made from aluminum and is in two parts; the upper section only needs to be detached if the spark plugs or valve cover have to be accessed and not the whole intake manifold. Among things one needs to do when the complete intake manifold is pulled off is to depressurize the fuel system, though the upper manifold removal let's you skip the process. The first step is to remove the negative battery terminal cable, after that the Electrical Connector of Intake Air Temperature Sensor, thereafter the Air Intake Tube and Air Filter Upper Housing is to be removed. Subsequently, remove the electrical connectors at the Idle Air Control motor, Throttle Position Signal output unit, and Manifold Absolute Pressure sensing point; as well as the vacuum lines from numerous parts. Accelerator cable as well as, if the car has one, the cruise control and transmission control cables must be disconnected. Bolts on the EGR pipe on the EGR valve and intake manifold must be taken out together with the oil dipstick. If only upper intake manifold is being removed it is required to undo manifold support bracket bolt, uncouple the upper intake manifold attaching bolt, and lift the manifold off. Another manifold gasket is to be applied when refitting, before tightening the bolts, the central ones first, apply uniform and progressive force. More specifically, for full intake manifold removal, the Coolant Temperature Sensor electrical connector has to be disconnected, as well as the fuel injector harness connectors, fuel rail, fuel pressure regulator and, finally, the fuel injectors which have to be removed as a single piece. If changing or reading the intake manifold plenum, the throttle body should be taken off; but if only changing the cylinder head it can stay there. It is recommended that the intake manifold support bracket bolts and the intake manifold bolts and washers be removed and this would enable the intake manifold and gasket to be replaced. For inspection, straightedge and feeler gauge ought to be used on the mating surfaces in order to identify warpage and where warpage embraces limits, resurfacing or replacement is required. When bolting the manifold back, the intake manifold gasket should be new and the bolts tightened evenly starting with the inner ones to avoid warping of the manifold then the rest of it is the reverse of the process of removing the manifold.